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Technical Paper

Simultaneous Real-Time Measurements of NO and NO2 in Medium Duty Diesel Truck Exhaust

2007-04-16
2007-01-1329
The goal of the present work was to investigate the ability of the SEMTECH®-D Portable Emissions Measurement System (PEMS) to provide simultaneous, accurate, real-time (1Hz) measurements of NO and NO2 in vehicle exhaust. Extensive chassis dynamometer laboratory evaluation studies of the SEMTECH® system were conducted. The instantaneous (1Hz) NOx emissions were measured using a conventional chemiluminescence analyzer (CLA) and were compared to the sum of the instantaneous NO and NO2 measurements from the SEMTECH®-D. The sum of the NO and NO2 emissions measured by the SEMTECH® were in excellent agreement (within 95% in most cases) with the total NOx measurements from the conventional CLA. During the laboratory evaluation studies, several Federal Test Procedure (FTP) drive cycles were conducted. Examples of the NO and NO2 concentration and mass emissions measured using the SEMTECH®-D are presented along with the corresponding SEMTECH®-D detection limits.
Technical Paper

Correlation Study Between On-road Drive-by Noise and Reverberation Room Body Transparency Tests

2009-05-19
2009-01-2227
A quiet passenger compartment is highly desired by today's customers. Vehicle design teams spend significant time and resources to minimize the vehicle's interior noise due to different exterior noise sources. Drive-by vehicles on the highways generate one of these noise sources. The objective of this study is to establish a correlation between customer's on-road experience due to drive-by noise and Noise Reduction Level (body transparency) tests conducted in a reverberation room. The average Noise Reduction Level (NRL) obtained in the reverberation room tests correlates (R2=0.89) with the peak loudness of on road tests. A sound quality listening study was also conducted to determine the most preferred NRL spectral distribution and its frequency range sensitivity.
Technical Paper

Simulation of Straight-Line Type Assist Characteristic of Electric Power-Assisted Steering

2004-03-08
2004-01-1107
Electric Power-Assisted Steering (EPAS) is a new power steering technology that will define the future of vehicle steering. The assist of EPAS is the function of the steering wheel torque and vehicle velocity. The assist characteristic of EPAS is set by control software, which is one of the key issues of EPAS. The straight-line type assist characteristic has been used in some current EPAS products, but its influence on the steering maneuverability and road feel hasn't been explicitly studied in theory. In this paper, the straight-line type assist characteristic is analyzed theoretically. Then a whole vehicle dynamic model used to study the straight-line type assist characteristic is built with ADAMS/Car and validated with DCF (Driver Control Files) mode of ADAMS/Car. Based on the whole vehicle dynamic model, the straight-line type assist characteristic's influence on the steering maneuverability and road feel is investigated.
Technical Paper

2005 Ford GT - Vehicle Aerodynamics - Updating a Legend

2004-03-08
2004-01-1254
This paper documents the processes and methods used by the Ford GT team to meet aerodynamic targets. Methods included Computational Fluid Dynamics (CFD) analysis, wind tunnel experiments (both full-size and scale model), and on-road experiments and measurements. The goal of the team was to enhance both the high-speed stability and track performance of the GT. As a result of the development process, significant front and rear downforce was achieved while meeting the overall drag target.
Technical Paper

Verification of Accelerated PM Loading for DPF Qualification Studies

2009-04-20
2009-01-1089
High gas prices combined with demand for improved fuel economy have prompted increased interest in diesel engine applications for both light-duty and heavy-duty vehicles. The development of aftertreatment systems for these vehicles requires significant investments of capital and time. A reliable and robust qualification testing procedure will allow for more rapid development with lower associated costs. Qualification testing for DPFs has its basis in methods similar to DOCs but also incorporates a PM loading method and regeneration testing of loaded samples. This paper examines the effects of accelerated loading using a PM generator and compares PM generator loaded DPFs to engine dynamometer loaded samples. DPFs were evaluated based on pressure drop and regeneration performance for samples loaded slowly and for samples loaded under accelerated conditions. A regeneration reactor was designed and built to help evaluate the DPFs loaded using the PM generator and an engine dynamometer.
Technical Paper

Mexico City Traffic and Los Angeles City Traffic Testing: An Approach to Test Route Development for Results Homologation

2012-09-17
2012-01-1808
Vehicle testing on public roads is used by the automotive community in different locations to evaluate the noise characteristics of brake systems under typical customer usage conditions. These tests are generally carried out on different locations and show results with questionable compatibility as has been concluded on several investigations over the last years [1]. Global projects on the other hand mandate to have tests that can represent vehicle usage in several types of environments in order to have reliable indicators of performance on different conditions. This paper suggests a method to characterize roads on different sites and modify the route to match a specific target.
Technical Paper

Effect of Road Excitations on Driveline Output Torque Measurements

2011-05-17
2011-01-1538
This paper presents the characterization of the random noise in driveline output shaft torque measurements that is commonly induced by road disturbances. To investigate the interaction between the shaft torque and road side excitation, torque signals are measured using a magnetoelastic torque sensor, as well as a conventional strain gauge sensor, under various types of road surfaces and conditions such as unevenness. A generalized de-trending method for producing a stationary random signal is first conducted. Statistical methods, in particular the probability density function and transform technique, are utilized to provide an evident signature for identifying the road excitation effect on the vehicle output shaft torque. Analysis results show how the road surface can act as a disturbance input to the vehicle shaft torque.
Technical Paper

Development of Universal Brake Test Data Exchange Format and Evaluation Standard

2010-10-10
2010-01-1698
Brake system development and testing is spread over vehicle manufacturers, system and component suppliers. Test equipment from different sources, even resulting from different technology generations, different data analysis and report tools - comprising different and sometimes undocumented algorithms - lead to a difficult exchange and analysis of test results and, at the same time, contributes to unwanted test variability. Other studies regarding the test variability brought up that only a unified and unambiguous data format will allow a meaningful and comparative evaluation of these data and only standardization will reveal the actual reasons of test variability. The text at hand illustrates that a substantial part of test variability is caused by a misinterpretation of data and/or by the application of different algorithms.
Journal Article

Modeling and Experimental Investigation of Tire Cavity Noise Generation Mechanisms for a Rolling Tire

2009-05-19
2009-01-2104
Tire cavity noise refers to the excitation of the acoustic mode of a tire cavity. The noise exhibits itself as sharp resonance-like peaks with frequencies typically in the range of 190-250Hz. For a rolling tire, the tire contact with the road moves relative to the tire. Furthermore, the load on the tire breaks the circular symmetry of the tire. Consequently, the peak frequency of the cavity noise shows dependence on the tire load and the vehicle speed. There are no models that simultaneously take these two factors into consideration. In this paper, we propose an analytical model and present experimental verifications of predictions on the noise peak frequency and its dependence on the tire load and vehicle speed. A wireless experimental measurement system is also presented which enables the measurement of tire cavity frequency for both non-rolling and rolling conditions.
Technical Paper

CFD Prediction of Automotive Windshield Defrost Pattern

1999-03-01
1999-01-1203
In this investigation, Computational Fluid Dynamics (CFD) is used to numerically simulate vehicle defroster performance. The general-purpose CFD package FLUENT/UNS is used to perform the numerical simulation. It is difficult to accurately model the actual flow and conjugate heat transfer phenomena in the vicinity of the windshield because of the complexity of the geometry and flow conditions, including the correct turbulence model. The objectives of this study are to quantify the velocity field in the vicinity of the windshield due to defroster jet flow, predict the windshield defrost pattern, and validate the use of CFD simulation in the engineering design and development process. This paper identifies the computational methodology and presents the simulation results. It also contains the hot-wire validation measurements for the velocity field as well as the cold room testing of the defroster performance.
Technical Paper

Development of a Thermal Fatigue Test Bench for Cylinder Head Materials

2018-04-03
2018-01-1410
An innovative specimen design and test system for thermal fatigue (TF) analysis is developed to compare the fatigue behavior of different cylinder head materials under realistic cyclic thermal loadings. Finite element analyses were performed to optimize the specimen geometry and thermal cycles. The reduced section of the TF specimen is heated locally by a high frequency induction heater and cooled by compressed air. The mechanical strain is then induced internally by the non-uniform thermal gradient generated within the specimen to closely simulate what valve bridges in cylinder heads experience in real operation. The resulting fatigue life is a function not only of the inherent fatigue resistance of the alloys, but also of other relevant properties such as thermal conductivity, modulus of elasticity, and coefficient of thermal expansion. This test is an essential tool for comparing different alloys for thermal fatigue applications.
Technical Paper

A Side Impact Taxonomy for USA Field Data

2018-04-03
2018-01-1331
An eleven-group taxonomy was created to classify real-world side crashes from the Crashworthiness Data System (CDS) component of the National Automotive Sampling System (NASS). Three steps were taken to develop the classification scheme: (1) side-impact towaway crashes were identified by examining 1987-2016 model year light passenger vehicles with Collision Deformation Classification (CDC) data from the 1997-2015 calendar years of NASS; (2) case reviews, engineering judgments, and categorization assessments were conducted on these data to produce the eleven-group taxonomy; and (3) taxonomic groups were reviewed relative to regulated crash test procedures. Two of the taxonomic groups were found to have the most frequent crash types, each contributing approximately 22% to the total, followed closely by a third taxonomic group contributing approximately 19%.
Technical Paper

Robust Methodology for Fast Crank Angle Based Temperature Measurement

2016-04-05
2016-01-1072
The paper presents a measurement methodology which combines a fine-wire thermocouple with input reconstruction in order to measure crank angle resolved temperature in an engine air-intake system. Thermocouples that are of practical use in engine experiments tend to have a large time constant which affects measurement accuracy during rapid temperature transients. Input reconstruction methods have previously been applied to thermocouples but have not been specifically used in combination with an ultra-thin uninsulated wire thermocouple to investigate cyclic intake temperature behavior. Accurate measurement results are of interest to improve the validity of many crank-angle resolved engine models. An unshielded thermocouple sensor has been developed which is rigid enough to withstand the aerodynamic forces of the intake air.
Technical Paper

Integration and Validation of a Thermal Energy Storage System for Electric Vehicle Cabin Heating

2017-03-28
2017-01-0183
It is widely recognized in the automotive industry that, in very cold climatic conditions, the driving range of an Electric Vehicle (EV) can be reduced by 50% or more. In an effort to minimize the EV range penalty, a novel thermal energy storage system has been designed to provide cabin heating in EVs and Plug-in Hybrid Electric Vehicles (PHEVs) by using an advanced phase change material (PCM). This system is known as the Electrical PCM-based Thermal Heating System (ePATHS) [1, 2]. When the EV is connected to the electric grid to charge its traction battery, the ePATHS system is also “charged” with thermal energy. The stored heat is subsequently deployed for cabin comfort heating during driving, for example during commuting to and from work. The ePATHS system, especially the PCM heat exchanger component, has gone through substantial redesign in order to meet functionality and commercialization requirements.
Technical Paper

A Method for Rapid Durability Test Development

2017-03-28
2017-01-0199
Designing a durability test for an automatic transmission that appropriately reflects customer usage during the lifetime of the vehicle is a formidable task; while the transmission and its components must survive severe usage, overdesigning components leads to unnecessary weight, increased fuel consumption and increased emissions. Damage to transmission components is a function of many parameters including customer driving habits and vehicle and transmission characteristics such as weight, powertrain calibration, and gear ratios. Additionally, in some cases durability tests are required to verify only a subset of the total parameter space, for example, verifying only component modifications. Lastly, the ideal durability test is designed to impose the worst case loading conditions for the maximum number of internal components, be as short as practicable to reduce testing time, with minimal variability between tests in order to optimize test equipment and personnel resources.
Technical Paper

A Comparative Study of Two RVE Modelling Methods for Chopped Carbon Fiber SMC

2017-03-28
2017-01-0224
To advance vehicle lightweighting, chopped carbon fiber sheet molding compound (SMC) is identified as a promising material to replace metals. However, there are no effective tools and methods to predict the mechanical property of the chopped carbon fiber SMC due to the high complexity in microstructure features and the anisotropic properties. In this paper, a Representative Volume Element (RVE) approach is used to model the SMC microstructure. Two modeling methods, the Voronoi diagram-based method and the chip packing method, are developed to populate the RVE. The elastic moduli of the RVE are calculated and the two methods are compared with experimental tensile test conduct using Digital Image Correlation (DIC). Furthermore, the advantages and shortcomings of these two methods are discussed in terms of the required input information and the convenience of use in the integrated processing-microstructure-property analysis.
Technical Paper

Correlating Laboratory Oil Aerosol Coking Rig Tests to Diesel Engine Tests to Understand the Mechanisms Responsible for Turbocharger Compressor Coking

2017-03-28
2017-01-0887
Deposit formation within turbocharger compressor housings can lead to compressor efficiency degradation. This loss of turbo efficiency may degrade fuel economy and increase CO2 and NOx emissions. To understand the role that engine oil composition and formulation play in deposit formation, five different lubricants were run in a fired engine test while monitoring turbocharger compressor efficiency over time. Base stock group, additive package, and viscosity modifier treat rate were varied in the lubricants tested. After each test was completed the turbocharger compressor cover and back plate deposits were characterized. A laboratory oil mist coking rig has also been constructed, which generated deposits having the same characteristics as those from the engine tests. By analyzing results from both lab and engine tests, correlations between deposit characteristics and their effect on compressor efficiency were observed.
Technical Paper

Impact of Pre-Study Exploration on System Usability Scale and Task Success Rates for Automotive Interfaces

2017-03-28
2017-01-1385
Measurement of usability with the System Usability Scale (SUS) is successfully applied to products in many industries. The benefit of any measurement scale, however, is limited by the repeatability of the associated testing process. For SUS, these factors can include sample size, study protocol, previous experience, and pre study exposure to the system being tested. Differences in user exposure can influence the usability assessment of interfaces which could affect the validity of SUS scores.
Technical Paper

An Indirect Occupancy Detection and Occupant Counting System Using Motion Sensors

2017-03-28
2017-01-1442
This paper proposes a low-cost but indirect method for occupancy detection and occupant counting purpose in current and future automotive systems. It can serve as either a way to determine the number of occupants riding inside a car or a way to complement the other devices in determining the occupancy. The proposed method is useful for various mobility applications including car rental, fleet management, taxi, car sharing, occupancy in autonomous vehicles, etc. It utilizes existing on-board motion sensor measurements, such as those used in the vehicle stability control function, together with door open and closed status. The vehicle’s motion signature in response to an occupant’s boarding and alighting is first extracted from the motion sensors that measure the responses of the vehicle body. Then the weights of the occupants are estimated by fitting the vehicle responses with a transient vehicle dynamics model.
Technical Paper

A Test Method to Assess Interactions and Compatibility of Inflatable Seatbelts with Child Restraint Systems

2017-03-28
2017-01-1448
Ford Motor Company introduced the automotive industry’s first second row inflatable seatbelt system in 2011. The system is currently available in the outboard seating positions of the second row of several Ford and Lincoln models. An important consideration for this system is the interaction with child restraint systems (CRS) when it is used to install a CRS or used in conjunction with belt position booster. A novel test methodology to assess the interaction of CRS with Ford and Lincoln inflatable seatbelts through frontal impact sled tests is explained. Details of test methods including construction of additional fixtures and hardware are highlighted. This procedure is designed to enable test labs capable of running Federal Motor Vehicle Safety Standard (FMVSS) 213 testing to adapt this test method, with minimal fabrication, by utilizing existing test benches.
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