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In this paper, responses from a vehicle's suspension, chassis and body, are used to demonstrate a methodology to optimize physical test results. It is well known that there is a variability effect due to an increase of wheel unsprung mass (due to loads measurement fixturing), tire pressure, speed, etc. This paper quantifies loading variability due to Wheel Force Transducer (WFT) unsprung mass by using a rainflow cycle counting domain. Also, presents a proving ground-to-test correlation study and the data reduction techniques that are used in road simulation test development to identify the most nominal road load measurement. Fundamental technical information and analytical methodology useful in overall vehicle durability testing are discussed. Durability testing in a laboratory is designed to correlate fatigue damage rig to road. A Proving Ground (PG) loading history is often acquired by running an instrumented vehicle over one or more PG events with various drivers.

In this paper, loads acting on driveline components during an entire proving ground (PG) durability schedule are used to demonstrate the methodology of optimizing driveline performance reliability using both physical and computational methods. It is well known that there is an effect of driver variability on the driveline component loads. Yet, this effect has not been quantified in the past for lack of experimental data from multiple drivers and reliable data analysis methods. This paper presents the data reduction techniques that are used to identify the extreme driver performance and to extrapolate the short-term measurement to long-term data for driveline performance reliability. The driveline loading variability is made evident in the rotating moment histogram domain. This paper also introduces the concept for a simulation model to predict the driveline component loads based on a complete proving grounds schedule. A model-to-test correlation is also performed in this paper.

The LEV II and SULEV/PZEV emission standards legislated by the US EPA and the Californian ARB will require continuous reduction in the vehicles' emission over the next several years. Similar requirements are under discussion in the European Union (EU) in the EU Stage V program. These future emission standards will require a more efficient after treatment device that exhibits high activity and excellent durabilty over an extended lifetime. The present study summarizes the findings of a joint development program targeting such demanding future emission challenges, which can only be met by a close and intensive co-operation of the individual expert teams. The use of active systems, e.g. HC-adsorber or electrically heated light-off catalysts, was not considered in this study. The following parameters were investigated in detail: The development of a high-tech three-way catalyst technology is described being tailored for applications on ultra thin wall ceramic substrates (UTWS).

Based on the results of “An Evaluation of the Mechanical Properties of Wheel Force Sensors and their Impact on to the Data Collected During Different Driving Manoeuvres” Herrmann et al. (SAE Paper 05M-254) a second, detailed investigation has been started to acquire additional information. In this previous investigation, it has been found out, that a difference in mass can be clearly identified in the signals. The current paper summarizes the results of a detailed investigation, which has been performed at DaimlerChrysler Stress Lab in Auburn Hills, with a fully equipped vehicle - a set of 2/4 Wheel Force Sensors plus several acceleration sensors as well. Through careful research and testing it is expected that the differences in the dynamic behavior can be specified with better accuracy than in the previous study.

Hot Isostatic Pressing (HIP) has been routinely used to densify castings for aerospace and medical applications for over 30 years. While HIP is widely known to improve the toughness and fatigue life of castings through the healing of internal porosity, it has been perceived as too expensive for most cast aluminum alloys for automotive applications. Recent developments suggest that the cost effectiveness of certain special HIP processes should be revisited due to reductions in process cost and improvements in throughput. This paper will evaluate the Densal® II process applied to a front aluminum steering knuckle. Two casting processes representing differing levels of relative cost and quality were evaluated. The first was Alcoa's VRC/PRC process, a metal mold process with bottom fill, evacuation before fill and pressurization after fill. This is considered to be a premium quality, but higher cost casting process that is already qualified for this application.

Traditionally, high-strength low-alloy (HSLA) steel is used for automotive vehicle weight reduction in the North American automotive industry. Dual phase (DP) high strength steel has gained great attention because it provides a combination of high strength and good formability. The main advantage of DP steel is the high ratio of tensile strength to yield strength, which provides more flexibility in stamping and higher energy absorption in a component crush event. This study compares the performances of DP and HSLA steel grades in stamping processes and component crush events, as shown in a typical automotive unibody inner rail. Simulation results show that DP steel offers more uniform strain distribution, improved formability, and better crush performance than conventional HSLA steel.

Silicon Carbide (SiC) based high temperature semiconductor gas sensors were tested for potential applications in the closed-loop control of NOx storage catalytic converters. The exhaust gas composition behind a storage catalyst was simulated by synthetic gas mixtures supplied from a gas blending manifold. In lean oxidizing ambients the sensors produced signals opposite in sign upon the appearance of NOx on the one hand and mixtures of HC and CO on the other hand. Transient gas measurements revealed response times ranging between several milliseconds for HC and several seconds for NOx. These features render SiC based sensors potentially useful for the control of NOx storage catalytic converters.

The staircase fatigue testing method is a recognized method for determining the fatigue limit of powertrain components. The purpose of this paper is to improve upon existing standards by adding common practices that will ensure a higher degree of statistical accuracy in the data. This includes specifying appropriate sample sizes, stress increments and initial load conditions, as well as making suggestions for appropriate methods of analyzing the data. Two methods (Dixon and Mood method and probit analysis method) are selected and compared in terms of relative percent difference on four parameters (mean, standard deviation, B10 fatigue strength and B50 fatigue strength). The staircase data are obtained by simulations from normal and lognormal fatigue limit distributions.

Historically, pump noise can be a contributor to customer dissatisfaction with automatic transmissions. In this paper, a Shainin experiment was conducted to identify all probable root causes for pump noise on a production RWD transmission. Sample transmissions were selected following subjective evaluations. Noise was objectively measured in the lab using a microphone and an accelerometer. The study was conducted following a systematic Shainin statistical engineering methodology, which included the following major steps: selection of the test measure using the isoplot technique, selection of Best of Best (BOB) and Worst of Worst (WOW) transmissions, assessment of assembly variation, component search, and pair-wise comparisons. The study successfully highlighted the key variables on the drive gear involute profile, which are now being tightly controlled for improved noise characteristics.

An extensive digital simulation study on lift devices that interact with human operators in DaimlerChrysler automotive assembly plants has been initiated and deployed. This digital mock-up of human-machine workcells is to scientifically evaluate and further certify a number of typical commercial lift devices that are served in car-assembly operations. The entire model is based on human biomechanical Jacobian relationship, as a fundamental kinematic structure, to predict human body instantaneous joint-torque distribution when the human is working with a certain payload. The developed modeling and simulation system will play a pivotal role in proactive ergonomic prediction, verification and digital certification in car advance manufacturing engineering processes.

Sheet metal stamping involves a system of complex tribological (friction, lubrication, and wear), heat transfer, and material strain interactions. Accurate coefficient of friction, strain, and lubrication regime data is required to allow proper modeling of the various sheet stamping processes. In addition, non-intrusive means of monitoring the coefficient of friction in production stamping operations would be of assistance for efficiently maintaining proper stamping quality and to indicate when adjustments to the various stamping parameters, including maintenance, would be advantageous. One of the key sub-systems of the sheet metal stamping process is the draw bead. This paper presents an investigation of the tribology of the draw bead using a Draw Bead Simulator (DBS) Machine and automotive zinc-coated sheet steels. The investigation and findings include: 1) A new, non-intrusive method of measuring the surface temperature of the sheet steel as it passes through the draw bead.

During the initial vehicle design phase and as the first prototypes are built, extensive on-board instrumentation and data acquisition is required at the proving grounds (PG). The data is used for various types of testing and analysis. During this phase of development very few parts and assembly components are available for physical test. The objective is to develop a component test for the truck box. This test can be run without suspension parts during the early stages of the vehicle development. A further objective is to correlate the test to FEA models and actual Proving Ground full vehicle test results.

Managing regulatory content is a complex process for any industry, but particularly for the automotive industry, which is heavily regulated. Several approaches for managing content are discussed along with implications for the industry. The response of an Original Equipment Manufacturer (OEM) to the recent European Parliament End-of-Life Vehicle Directive (EU 2000/53/EC-ELVs)1 is discussed from a North American perspective as well as trickle down expectations for the automotive supply base. Design, sourcing and labeling issues associated with the ELV directive as well as domestic regulations are discussed.

The homogeneous charge, compression-ignition (HCCI) combustion process has the potential to significantly reduce NOx and particulate emissions, while achieving high thermal efficiency and the capability of operating with a wide variety of fuels. This makes the HCCI engine an attractive technology that can ostensibly provide diesel-like fuel efficiency and very low emissions, which may allow emissions compliance to occur without relying on lean aftertreatment systems.

High vacuum purge enhances the performance of an automotive vapor canister by increasing working capacity and decreasing Diurnal Breathing Loss (DBL) emissions. These improvements are significant because high vacuum purge can potentially be adapted for use in an automotive evaporative emissions system. These benefits were demonstrated by conducting multiple aging cycles at ambient, low, medium, and high vacuum levels. Effects on gasoline working capacity, butane capacity, accumulated hydrocarbon heel, and DBL performance were then compared and discussed.

The recent trends of increasing driveline torque and use of traction control devices call for increasingly higher durability capacity from driveline components. Bench and vehicle durability tests are often used to validate designs, but they are not cost-effective and take months to complete. Traditional finite element analysis (FEA) procedures have been used effectively in the re-design of driveline components to reduce stress, and occasionally, to predict fatigue life. But in the case of certain rotating components, such as the Axle Differential Case, where the component sees large stress/strain fluctuations within the course of one complete rotation, even under constant input torque, historical fatigue analysis (when conducted) yields very conservative results. The axle differential case tends to be one of the weakest links in the rear axle assembly. Therefore, there is a crucial need for analytical methods to more accurately predict fatigue life to reduce testing time and cost.

The effect of forming strains on the fatigue behavior of an automotive mild steel, interstitial free steel, was studied after being prestrained by balanced biaxial stretch and plane strain. In the long life region, higher than 5×105 reversals, prestrain improves fatigue resistance. In the short life region, prestrain reduces fatigue resistance. At even shorter fatigue lives, the detrimental effect of prestrain diminishes. For plane strains, the fatigue behavior is anisotropic. In the direction perpendicular to the major strain, the steel exhibits much better fatigue resistance than in the direction parallel to the major strain.

In a vehicle NVH development and refinement phase, it is necessary to understand the source of the noise and vibration from various powertrain and drivetrain mechanisms. The noise and vibration generated by a drivetrain in a vehicle is a complicate but significant source of physical mechanism, which might become important issues in early or later phase of the vehicle development. For the diagnostic purpose of the drivetrain, a rear-wheel drive (RWD) vehicle in early development phase has been used to measure the bending and torsional vibration of the drivetrain, as well as the vehicle interior noise simultaneously, while the vehicle is running up and down under quasi-steady state on a chassis dynamometer. The lower frequency resonances of torsional and bending vibrations from the drivetrain are correlated with the vehicle interior boom or overall loudness.

Durability of automotive structures is a primary engineering consideration that is required to be assessed at every design and development stage. Due to limitations of the analytical and experimental tools, the current practice in the automotive industry is to conduct a new data acquisition over a proving ground schedule whenever there are changes in the suspension parameters. This is a time-consuming and expensive operation. This paper provides guidelines for product teams to determine if a new vehicle data acquisition is needed when there are changes in vehicle parameters, and the corresponding effect on Road Test Simulator (RTS) drive file development. The application of this methodology to a truck with and without tuned suspension parameters is described in detail.

Throughout its history, the automobile has served the utilitarian purpose of transportation quite well. However, until recently, vehicle occupants have had little else to do while proceeding from point "A'' to point "B.'' The phenomenal improvements in computing and communication technologies promise to evolve the driving experience. Like never before, new opportunities to make driving more efficient and engaging are becoming available. The challenge will be to develop the right combination of technology, safety, design and user interface that creates a product popular with customers.