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Journal Article

Influence of Test Procedure on Friction Behavior and its Repeatability in Dynamometer Brake Performance Testing

The efforts of the ISO “Test Variability Task Force” have been aimed at improving the understanding and at reducing brake dynamometer test variability during performance testing. In addition, dynamometer test results have been compared and correlated to vehicle testing. Even though there is already a vast amount of anecdotal evidence confirming the fact that different procedures generate different friction coefficients on the same brake corner, the availability of supporting data to the industry has been elusive up to this point. To overcome this issue, this paper focuses on assessing friction levels, friction coefficient sensitivity, and repeatability under ECE, GB, ISO, JASO, and SAE laboratory friction evaluation tests.
Technical Paper

Clustering and Scaling of Naturalistic Forward Collision Warning Events Based on Expert Judgments

The objectives of this study were a) to determine how expert judges categorized valid Integrated Vehicle-Based Safety Systems (IVBSS) Forward Collision Warning (FCW) events from review of naturalistic driving data; and b) to determine how consistent these categorizations were across the judges working in pairs. FCW event data were gathered from 108 drivers who drove instrumented vehicles for 6 weeks each. The data included video of the driver and road scene ahead, beside, and behind the vehicle; audio of the FCW alert onset; and engineering data such as speed and braking applications. Six automotive safety experts examined 197 ‘valid’ (i.e., conditions met design intent) FCW events and categorized each according to a taxonomy of primary contributing factors. Results indicated that of these valid FCW events, between 55% and 73% could be considered ‘nuisance alerts’ by the driver.

Future Development of EcoBoost Technology

Ford's EcoBoost GTDI engine technology (Gasoline Direct Injection, Turbo-charging and Downsizing) is being successfully implemented in the market place with the EcoBoost option accounting for significant volumes in vehicle lines as diverse as the F150 pickup truck, Edge CUV and the Lincoln MKS luxury sedan. A logical question would be what comes after GTDI? This presentation will review some of the technologies that will be required for further improvements in CO2, efficiency and performance building on the EcoBoost foundation as well as some of the challenges inherent in the new technologies and approaches. Presenter Eric W. Curtis, Ford Motor Co.

Ford: Driving Electric Car Efficiency

The Focus Electric is Ford�s first full-featured 5 passenger battery electric vehicle. The engineering team set our sights on achieving best-in-class function and efficiency and was successful with an EPA certified 1XX MPGe and range XXX then the facing competition allowing for a slightly lower capacity battery pack and larger vehicle without customer trade-off. We briefly overview the engineering method and technologies employed to deliver the results as well as sharing some of the functional challenges unique to this type of vehicle. Presenter Charles Gray, Ford Motor Co.

The Future (& Past) of Electrified Vehicles

The presentation offers a brief history of the electric vehicle and parallels the realities of those early vehicles with the challenges and solutions of the electrified vehicles coming to market today. A technology evolution for every major component of these vehicles has now made this mode of transportation viable. The Focus Electric is Ford's first electric passenger car utilizing the advanced technology developments to meet the needs of electric car buyers in this emerging market. Presenter Charles Gray, Ford Motor Co.
Technical Paper

A Simplified Approach to Quantifying Gear Rattle Noise Using Envelope Analysis

The present work discusses an objective test and analysis method developed to quickly quantify steering gear rattle noise heard in a vehicle. Utilizing envelope analysis on the time history data of the rattle signal, the resulting method is simple, fast, practical and yields a single-valued metric which correlates well to subjective measures of rattle noise. In contrast to many other rattle analysis methods, the approach discussed here is completed in the time domain. As applied to rattle noise produced by automotive electric steering systems, the metric produced with this analysis method correlates well with subjective appraisals of vehicle-level rattle noise performance. Lastly, this method can also be extended to rattle measurements at the component and subcomponent level.
Technical Paper

Evolution of Automotive Test Equipment in the Service Bay

Most people still remember the introduction of the IBM PC in 1981 and the first Microsoft Windows operating system in 1985. These were the pioneering technologies that started a revolution in automotive test equipment in the service bay. What was once a purely mechanical garage environment where information was published annually in large paper manuals has evolved into a highly technical computing environment. Today vehicle networks link onboard vehicle control systems with diagnostic systems and updated service information is published daily over the Internet. A lot has changed over the last twenty years, and manufacturers of diagnostic test equipment are learning to deal with the constantly evolving computing platforms and host operating systems. This paper traces the history of automotive diagnostic equipment at Ford Motor Company and shares some of the hard lessons learned from the early systems.
Technical Paper

Challenges of adopting new Lighting Technologies on Emerging Markets

Emerging markets and South America in particular, have quickly become the cornerstone of major automotive companies in recent years. Currently, all major players are located in the region, and this has created an excellent environment for developing market-tailored products. The trend in the design and technology community is one which allows the final customer to improve his own safety and reduce overall power consumption. Throughout the entire automotive industry, the lighting system has always had a very important role to play during its long history. In the past 50 years, vehicular lighting has achieved an important status due to its close relationship by enhancing passenger and vehicle security. In addition, there is still room for improvement in the halogen front lighting system. Particularly, it is of utmost importance to highlight the implementation of NEO (new efficient optics).
Technical Paper

Engine Reliability Through Infant Mortality Mitigation: Literature Review

Internal combustion engines are designed to meet the high power, low fuel consumption and also, low exhaust emissions. The engine running conditions is valid the concept that, the expectative is very high because of the variety of operating conditions like cold start, frequent start and stop, time high speed and load, traditional gasoline, mix of gasoline and alcohol and finally, alcohol fuel only. Considering such demand, this paper explains the relationship between the reliability bathtub curve, specifically the "Infant Mortality" portion. The bathtub curve describes failure rate as a function of time. The "Infant Mortality" portion of the curve is the initial section for which the failure (death) rate decreases with time (age). In general, these problems are related to manufacturing aspects or poor design definitions. With development of technology, hard failures, the ones that cause dependability, are becoming rare.
Journal Article

Diagnostics Design Process for Developmental Vehicles

In this paper a diagnostic design process is proposed for developmental vehicles where mainstream design process is not well-suited. First a review of current practice in on-board vehicle fault diagnostics design is presented with particular focus on the application of this process to the development of the Ford Escape Hybrid Electric Vehicle (HEV) program and a demonstration Fuel Cell Electric Vehicle (FCEV) program. Based on the review and evaluation of these experiences, a new tool for diagnostics design is proposed that promises to make the design more traceable, to reduce the repetition of work, and to improve understandability and reuse.
Journal Article

Cosmetic Corrosion Test for Aluminum Autobody Panels: Final Report

Over the past several years a task group within the SAE Automotive Corrosion and Protection (ACAP) Committee has conducted extensive on-vehicle field testing and numerous accelerated lab tests with the goal of establishing a standard accelerated test method for cosmetic corrosion evaluations of finished aluminum auto body panels. This project has been a cooperative effort with OEM, supplier, and consultant participation and was also supported in part by DOE through USAMP (AMD 309). The focus of this project has been the identification of a standardized accelerated cosmetic corrosion test that exhibits the same appearance, severity, and type of corrosion products that are exhibited on identical painted aluminum panels exposed to service relevant environments. Multi-year service relevant exposures were conducted by mounting panels on-vehicles in multiple locations in the US and Canada.
Technical Paper

Frictional and Acoustic Behavior of Automotive Interior Polymeric Material Pairs Under Environmental Conditions

As automotive manufacturers continue to increase their use of thermoplastics for interior and exterior components, there is a likelihood of squeaks due to material contacts. To address this issue, Ford's Body Chassis NVH Squeak and Rattle Prevention Engineering Department has developed a tester that can measure friction, and any accompanying audible sound, as a function of sliding velocity, normal load, surface roughness, and environmental factors. The Ford team has been using the tester to address manufacturing plant issues and to develop a database of polymeric material pairings that will be used as a guide for current and future designs to eliminate potential noise concerns. Based upon the database, along with a physical property analysis of the various plastic (viscoelastic) materials used in the interior, we are in the process of developing an analytical model which will be a tool to predict frictional behavior.
Technical Paper

Identification of the Optimum Vehicle Class for the Application of 42v Integrated Starter Generator

Today nearly all automotive manufacturers are developing motor-generator systems for improved fuel economy by implementing idling-stop and other power train enhancements. It is said that powertrain technology has always pioneered the development of automotive electronic control throughout history. The integrated starter generator (ISG) promises to expand the scope of powertrain control further through fuel economy improvement, emissions reduction, longitudinal vehicle dynamics improvement and customer feature enhancements. At the present time the cost imposed by usage of an ISG system is very high due mainly to its need for a power optimized 42V battery and high power electronics. This paper takes a critical look at the vehicle benefits attributable to ISG and its implementation costs over various vehicle classes.
Technical Paper

Regimes of Premixed Turbulent Combustion and Misfire Modeling in SI Engines

A review of flame kernel growth in SI engines and the regimes of premixed turbulent combustion showed that a misfire model based on regimes of premixed turbulent combustion was warranted[1]. The present study will further validate the misfire model and show that it has captured the dominating physics and avoided extremely complex, yet inefficient, models. Results showed that regimes of turbulent combustion could, indeed, be used for a concept-simple model to predict misfire limits in SI engines. Just as importantly, the entire regimes of premixed turbulent combustion in SI engines were also mapped out with the model.
Technical Paper

Oscillating Heat Transfer in Reversing Pipe Flow

Oscillating heat transfer is a fundamental phenomenon occurring in Stirling machines and IC engines. A group of relevant dimensionless numbers which characterize this problem is identified by dimensional analysis. The convective heat transfer coefficient, or Nusselt number, is a function of the Reynolds number, the Prandtl number, plus the dynamic Reynolds number and the dimensionless amplitude, when compressibility is not considered. The case for compressible fluid is more complicated. An experiential study confirms above analysis and results in a nonlinear longitudinal fluid temperature distribution in the pipe. The history effect is found to affect the heat transfer rate remarkably. A correlation equation for Nusselt number is obtained by multivariate analysis.
Technical Paper

Statistical Analysis of Vehicle High Mileage NVH Performance

High mileage NVH performance is one of the major concerns in vehicle design for long term customer satisfaction. The current paper is concerned with performance analysis of high mileage vehicles which cover four automobile manufacturers and five vehicle families of the same weight class based on subjective evaluation data. The analysis includes the assessment of five vehicle families from the following aspects: overall and NVH performances, performance by individual attribute, degradation history of each vehicle family, performance variation within each vehicle family. Since the data are statistical in nature, statistical methods are employed, numerically and graphically, in the analysis. The performance categories which exhibit most degradation are identified. The analysis method presented in this paper is applicable to any high mileage vehicle fleet subjective data. The knowledge derived in the study can be used as a guideline in designing vehicles for high mileage NVH robustness.
Technical Paper

Exhaust Valve Seat Leakage

A 1.9L four cylinder engine was evaluated for leakage of cylinder charge through the exhaust valve seats. Fast FID HC analyzer traces reveal leakage. Static leakdown tests do not correlate with the Fast FID measurement, unlike previously published reports for a different engine. The causes of exhaust valve seat leakage are likely to be Flakes of cylinder deposits lodging in the valve seat Valve seat distortion due to the thermal and pressure loading of the cylinder head structure Because deposit related effects are very history dependent, it is very difficult to obtain quantitative results. Some experimental observations: Static pressure leakage measurements show variation of leakage area with cylinder pressure, caused by flexing of the valve head. Dynamic leakage results are history dependent. Leakage is reduced after running at high speed/load, and gradually build up during extended light load low speed operation.
Technical Paper

Methods for Analyzing Order Spectra

Since many automobile NVH issues involve the analysis of order spectra it is highly important that the methods used should be accurate and consistent. A review of the literature shows little discussion of several key issues which could cause problems and possibly invalidate test results. Also, experience indicates that different methods may yield different results unless these key issues are dealt with. This paper compares four different approaches to order tracking as applied to typical engine sweep data: order analysis of conventional fixed frequency waterfall plots, synchronous sampling order tracking, computed digital order tracking, and Kalman filtering. It is shown that unless the analysis parameters are carefully chosen the results of the analysis may be in error. The major issues for the conventional fixed sampling rate waterfall method arise because sweeping the orders causes a frequency smearing effect.
Technical Paper

U.S. Automotive Corrosion Trends Over the Past Decade

Since 1985, the Body Division of the Automotive Corrosion and Prevention Committee of SAE (ACAP) has conducted biannual surveys of automotive body corrosion in the Detroit area. The purpose of these surveys is to track industry wide corrosion protection improvements and to make this information available for public consumption. The survey consists of a closed car parking lot survey checking for perforations, blisters, and surface rust. This paper reports the results of the five surveys conducted to date.
Technical Paper

Incremental Multiaxial Neuber Correction for Fatigue Analysis

Estimations of the elastic-plastic stress states at notches from elastic finite element results based on Neuber type of correction method have proven very useful for many engineering problems. While this approximation technique has been regularly used in simple fatigue analysis of components subjected to predominantly uniaxial loading, its extension into multiaxial cases has been limited to monotonic loading. This paper presents a technique which integrates the Neuber type of correction method with a three-dimensional cyclic stress-strain model. Three major elements are involved: 1) an assumed elastic-plastic loading path; 2) a one-to-one relationship between the given elastic and the corrected elastic-plastic loading history; and 3) a plasticity model for multiaxial cyclic stress-strain analysis. The technique is then illustrated to be capable of estimating complex yet stable cyclic stress and strain histories at a notch.