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Technical Paper

Experimental Determination of Automotive System Response Characteristics

Vehicle NVH performance is significantly affected by the dynamics of various primary systems. In the automotive industry, different design activities or vendors are responsible for designing various different systems simultaneously. Therefore, it is highly desirable to gain a better understanding of the individual system characteristics and the interaction between the primary systems to achieve a desirable overall NVH performance. Unfortunately, it is usually quite difficult to construct a proper fixture to accurately measure and quantify the actual uncoupled system characteristics. This paper examines an alternate approach of applying the FRF-based substructuring method to back-calculate the system response characteristics from the full vehicle system measurements. The results are then used to forward-compute the dynamic response of the vehicle, which are also validated by comparison to the direct response function measurements.
Technical Paper

Experimental Study of Automotive Heat Shield Geometry with Natural Convection and Radiation Boundary Conditions

Shielding a vehicle underbody is becoming a daunting task with increased exhaust temperatures due to emissions regulations and ever-increasing packaging constraints, which place components ever closer to exhaust systems. This experimental study was initiated to evaluate the two dimensional thermal effects of heat shield flange height and shield width in vehicle underbody idle conditions. The ultimate goal of this study is to develop a function to optimize the shape of heat shielding to achieve a specified floorpan temperature during vehicle idle conditions.
Technical Paper

A Comparison of Methods for Evaluating Automatic Transmission Fluid Effects on Friction Torque Capacity - A Study by the International Lubricant Standardization and Approval Committee (ILSAC) ATF Subcommittee

As part of the International Lubricant Standardization and Approval Committee's (ILSAC) goal of developing a global automatic transmission fluid (ATF) specification, members have been evaluating test methods that are currently used by various automotive manufacturers for qualifying ATF for use in their respective transmissions. This report deals with comparing test methods used for determining torque capacity in friction systems (shifting clutches). Three test methods were compared, the Plate Friction Test from the General Motors DEXRON®-III Specification, the Friction Durability Test from the Ford MERCON® Specification, and the Japanese Automotive Manufacturers Association Friction Test - JASO Method 348-95. Eight different fluids were evaluated. Friction parameters used in the comparison were breakaway friction, dynamic friction torque at midpoint and the end of engagement, and the ratio of end torque to midpoint torque.
Technical Paper

Use of Polyurethane Material Models for Simulating Leg-Form Impact in Different Explicit Finite Element Codes

Compressible plastic foams are used throughout the interior and bumper systems of modern automobiles for safety enhancement and damage prevention. Consequently, modeling of foams has become very important for automobile engineers. To date, most work has focused on predicting foam performance up to approximately 80% compression. However, in certain cases, it is important to predict the foam under maximum compression, or ‘bottoming-out.’ This paper uses one such case-a thin low-density bumper foam impacted by a pedestrian leg-form at 11.1 m/s-to investigate the ‘bottoming-out’ phenomenon. Multiple material models in three different explicit Finite Element Method (FEM) packages (RADIOSS, FCRASH, and LS-DYNA) were used to predict the performance. The finite element models consisted of a foam covered leg-form impacting a fixed bumper beam with a foam energy absorber.
Technical Paper

State of Knowledge and Current Challenges in Defrosting Automotive Windshields

Rapid and effective windshield defrosting has been the goal of various investigations by automotive engineers around the world. Car manufacturers have invested considerable resources to satisfy the thermal needs, safety requirements, and comfort demands of their customers. This paper addresses the climate control issues of defrosting automotive windshields. The paper summarizes the state of knowledge of the various approaches for improving defroster performance. Experimental as well as computational efforts, accompanied by heating techniques and heat boosters will be presented. The paper also features relevant measurement methods for airflow and thermal patterns, and discusses current challenges. Recommendations are made on where to focus engineering and design efforts given the state of present technologies.
Technical Paper

Front End Accessory Drive Program Management

Program Management organizes the different phases of new Front End Accessory Drive (FEAD) designs from inception providing lower cost, higher quality and shorter product development cycles. These outcomes are accomplished using a team concept to successfully incorporate simultaneous engineering, computer design/development methods, supplier input and other techniques.
Technical Paper

Three-Dimensional Simulations of Automotive Catalytic Converter Internal Flow

The three-dimensional non-reacting flow field inside a typical dual-monolith automotive catalytic converter was simulated using finite difference analysis. The monolithic brick resistance was formulated from the pressure gradient of fully developed laminar duct-flow and corrected for the entrance effect. This correlation was found to agree with experimental pressure drop data, and was introduced as an additional source term into the non-dimensional momentum governing equation within the brick. Flow distribution within the monolith was found to depend strongly on the diffuser performance, which is a complex function of flow Reynolds number, brick resistance, and inlet pipe length and bending angles. A distribution index was formulated to quantify the degree of non-uniformity at selected test cases covering ranges of flow conditions, brick types, and inlet conditions.
Technical Paper

Development of Diagnostic Tools in Automotive Electronics

Throughout the evolution of transportation technology the automotive industry has continually devised methods of diagnosing and servicing vehicle electrical and electronic concerns. Methodologies have always included special test equipment accompanied by volumes of printed manual procedures. Today's vehicle technology, with its highly interactive/integrated systems control capability, has brought on a new level of complexity and confusion to the service technician. In order to assist the technician in the diagnosis of microprocessor based control systems, the service industry has developed highly sophisticated on-board vehicle diagnostics as well as off-board computer based equipment. This paper describes the progression of service test equipment provided by Ford Motor Company to assist in vehicle electrical/electronic diagnostics. Similar to all industry manufacturers Ford Motor has devised both on-board and off-board systems which are required to fix the car right the first time.
Technical Paper

Modular Design and Methods to Optimize Seat Complete Assemblies

Modularity in product architecture and its significance in product development have become an important product design topics in the last few decades. Several Product Modularity definitions and methodologies were developed by many researchers; however, most of the definitions and concepts have proliferated to the extent that it is difficult to apply one universal definition for modular product architecture and in product development. Automotive seat modular strategy and key factors for consideration towards modular seat design and assemblies are the main focus of this work. The primary objectives are focused on the most “natural segmentation” of the seat elements (i.e., cushions, backs, trims, plastics, head restraints, etc.) to enable the greatest ease of final assembly and greatest flexibility for scalable feature offerings around common assembly “hard-points.”
Technical Paper

Improving Multi-Voltage Electrical System Performance with Smart Step-Down Converters

The demand for more features in a vehicle is growing at an extraordinary rate. This trend especially with emerging autonomous functions shows no sign of slowing. The energy requires to supply this ever growing system goes through multiple conversion, protection and other elements before it actually powers the loads. Considering the loss of each of these elements for a vehicle and multiplying the value by the total numbers of cars, underlines the need for an optimized electrical distribution system to power all loads efficiently. In this paper, Smart Step-Down Convertor is introduced as a power supply to power devices which operate at voltages below the power net voltage while protecting the power net and the devices against faults.
Technical Paper

A Methodology of Real-World Fuel Consumption Estimation: Part 1. Drive Cycles

To assess the fuel consumption of vehicles, three sets of input data are required; drive cycles, vehicle parameters, and environmental conditions. As the first part of a series of studies on real-world fuel consumption, this study focuses on the drive cycles. In principle, drive cycles should represent real-world usage. Some of them aim at a specific usage such as a city driving condition or an aggressive driving style. However, the definition of city or aggressive driving is very subjective and difficult to quantitatively correlate with the real-world usage. This study proposes a methodology to quantify the speed and dynamics of drive cycles, or vehicle speed traces in general, against the real-world usage. After reviewing parameter sets found in other studies, relative cubic speed (RCS) and positive kinetic energy (PKE) are selected to represent the speed and dynamics through energy flow balance at the wheels.
Technical Paper

The Search for a Truly International Radio Frequency Interference Standard

SAE J551a (radio interference from ignition systems) was the first Standard revised specifically for compatibility with international requirements. Subsequent revisions (presently 551g) have made it significantly more stringent than the standard used overseas. U.S. automotive manufacturers have voluntarily designed vehicles to conform since 1962, without the necessity of Federal regulation. Liaison with Canada resulted in the use of the SAE Standard when RFI regulations were promulgated. Twenty years international negotiations have resulted in a common concept for North American and world requirements. The RFI Subcommittee will continue harmonization toward the objective of achieving a worldwide standard.
Technical Paper

Vehicle Level EMC Testing Methodology and Correlation

This paper describes an indoor electromagnetic compatibility (EMC) testing facility designed for automotive testing over the 60 Hz to 18 GHz frequency range. The facility includes a large TEM cell, covering the 60 Hz to 20 MHz frequency range, and a state-of-the-art anechoic chamber, covering 20 MHz to 18 GHz. In addition to describing the test cells, this paper discusses testing methodology, automatic testing software and calibration. Data is presented depicting the electromagnetic field distribution in each test cell with and without the test vehicle in place. Data is also presented showing a typical field distribution near a high power shortwave transmitter site for correlation purposes.
Technical Paper

The Use of a Modified S.A.E. H-Point Machine in Assembly Plants

As part of a continuing Ford Motor Company program to improve the seating packages of production cars, a simplified in-plant method was developed to check seating variations in production vehicles. The method also provided information helpful in determining causal factors when any irregularities were found. Equipment necessary for checking was designed to be easily transported to any site.
Technical Paper


For the past seven years, the Ford Motor Company has been working on the development of catalytic exhaust treating systems designed to minimize the emission of certain vehicle exhaust gas constituents. In 1959, the development of a low-temperature, catalytic-converter system for the oxidation of exhaust gas hydrocarbons was described in a paper presented to the SAE. That system, which used vanadium pentoxide as the catalyst, has since been extensively developed in a program that included 250,000 miles of converter evaluation on vehicles. Many of the basic system requirements and problems covered in those tests are relevant in vehicle applications of a catalytic converter system with any type of catalyst. With the insertion of a carbon monoxide limit in the California Exhaust Standard, work on the low-temperature, catalytic converter system was discontinued since this system did not, and was not designed to, oxidize carbon monoxide.
Technical Paper

Correlation between vehicle interior noise and alternator radiated noise measured on bench test

In automotive industry, the interior quietness is a task that manufacturers are constantly improving for passenger comfort. In order to improve the interior quietness there are considered the contribution of structure borne and airborne noise. An alternator used in vehicles for generation of electricity can be considered as a contributor of airborne noise. Due to the characteristics of an alternator, it could radiate mechanical, aerodynamic and electromagnetic noise. The last two characteristics are normally perceived by customer during powertrain and idle evaluation. In this paper is presented correlation between interior noise measured on road test and alternator radiated noise measured on bench test.
Technical Paper

Ford's Facility Climate Change Initiatives: Lessons Learned From Early Action

Climate change initiatives such as carbon dioxide (CO2) inventory reporting, emissions trading, and carbon offsets projects are receiving increased public and corporate attention worldwide. Through early, voluntary actions, Ford Motor Company's manufacturing operations have gained first-hand experience with these emerging policy tools and our global, centralized approach has supported our participation in facility CO2 initiatives in a more cost-effective and operationally-efficient manner. Ford's early action has also developed internal expertise which enables us to share our lessons learned with others beginning to investigate climate change initiatives.
Technical Paper

The Handling of Non-Uniform Parts and Peak Hand Forces

Due to the challenges in quantifying hand loads in manufacturing environments it is often assumed that the load is evenly distributed between the hands, even when handling parts with non-uniform mass distribution. This study estimated hand loads for six female subjects, when handling a custom part in 8 different configurations (2 weights, 4 CofM locations). The calculated hand loads varied from 20 to 50% of the weight being handled. The magnitude of asymmetrical hand loading depended on both the part orientation and the location of the CoM. Based on this study the knowledge of part weight, CofM location and hand positioning will allow the users of digital human models to perform more realistic and reliable task analysis assessments as the force distributions will be more representative of the actual loading rather than simply assuming the load is evenly distributed between the hands.
Technical Paper

Determination of Source Contribution in Snowmobile Pass-by Noise Testing

As noise concerns for snowmobiles become of greater interest for governing bodies, standards such as SAE J192 are implemented for regulation. Specific to this pass-by noise standard, and unlike many other pass-by tests, multiple non-standardized test surfaces are allowed to be used. Manufacturers must understand how the machines behave during these tests to know how to best improve the measured noise levels. Data is presented that identifies the contributions of different sources for different snowmobiles on various test surface conditions. Adaptive resampling for Doppler removal, frequency response functions and order tracking methods are implemented in order to best understand what components affect the overall measurement during the pass-by noise test.
Technical Paper

Use of SEA to Support Sound Package Design Studies and Vehicle Target Setting

Statistical Energy Analysis (SEA) vehicle models are well-accepted tools for predicting the high-frequency interior acoustic effects of a design change to the structure or sound package of the vehicle. [1] SEA models do not strongly depend on geometric details, which allows SEA to be uniquely used as an analysis tool very early in the vehicle design phase to identify potential Noise, Vibration, and Harshness (NVH) issues caused by proposed changes to acoustic or vibration source levels, component materials, construction details, or sound package details of the vehicle. SEA models can also be used to suggest alternatives while the vehicle is still in the development stages to compensate for a predicted or known degradation to NVH in a vehicle due to a design or source level change. This paper presents a case study in which validation testing and an SEA model were combined to obtain recommendations for the most effective sound package changes to meet NVH targets.