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A predictive automatic gear shift system is currently under development. The system optimizes the gear shift process, taking the conditions of the road ahead into account, such that the fuel consumption is minimized. An essential part of the system is a module that predicts the vehicle speed dynamics: This calculates a speed trajectory, i.e. the most probable vehicle speed the driver will desire for the upcoming section of the route. In the paper the theoretical background for predicting the vehicle speed, and simulation results of the predictive shift algorithm are presented.

Advanced material modeling was conducted to describe the thermal-mechanical behavior of Boron Steel during hot stamping, a process in which blanks at 900 °C are formed and quenched between cold dies. Plastic deformation, thermal dilatation and phase transformation were incorporated in the constitutive model and a user-defined subroutine was developed to interface with LS-DYNA. Simulation was conducted on the hot stamping process of a door intrusion beam to gain insight into the physics of the process. Results showed significant influence of the thermal cycle on final product. It was also demonstrated that the program developed can be used as an early feasibility tool to determine baseline processing parameters and to detect potential defects in products without physical prototyping.

For a vehicle or repairable system, incidents (conditions) are neither necessarily independent nor identically distributed. Therefore, traditional statistical distributions like Weibull, Normal, etc, are no longer valid to estimate reliability. The Non-homogeneous Poisson process (NHPP) model can be used to predict reliability and warranty of the field product. It can also measure the reliability improvement during the development cycle. The NHPP model is discussed in this paper. In applying a NHHP model to reliability data on a repairable system, one may have few or no failures. This paper presents the I/100 and reliability derivations when the parameter β in the ROCOF function is assumed to have a known value.

In September 2003, the Mercedes Car Group set another milestone by introducing the fifth generation of automatic transmissions developed and manufactured in-house since 1960. The world's first 7-speed automatic transmission 7G-TRONIC is featured in the Mercedes-Benz S, SL, CL and E-Classes with V8 gasoline engines. Deduced from the demands of the requirement specifications, the 5-speed automatic transmission was decisively improved; the result is a clear increase in spontaneity, agility, fuel economy, and driving comfort for the customer. And because of the harmony between the vehicle and its powertrain, excellent results in the areas of performance, reduced emissions, comfort, and acoustics are obtained.

The US Automotive Materials Partnership (USAMP) and the US Department of Energy launched the Magnesium Powertrain Cast Components Project in 2001 to determine the feasibility and desirability of producing a magnesium-intensive engine; a V6 engine with a magnesium block, bedplate, oil pan, and front cover. In 2003 the Project reached mid-point and accomplished a successful Decision Gate Review for entry into the second half (Phase II) of the Project. Three tasks, comprising Phase I were completed: (1) evaluation of the most promising low-cost, creep-resistant magnesium alloys, (2) design of the engine components using the properties of the optimized alloys and creation of cost model to assess the cost/benefit of the magnesium-intensive engine, and (3) identification and prioritization of scientific research areas deemed by the project team to be critical for the use of magnesium in powertrain applications.

Load data representing severe customer usage is required during the chassis development process. One area of current research is the use of road profiles for predicting chassis loads. The most direct method of predicting these loads is to run dynamic simulations of the vehicle using numerous road profiles as the excitation. This onerous task may be avoided, and a greatly reduced number of simulations would be required, if roads having similar characteristics can be grouped. Currently, road profiles are characterized by their spectral content. It has been noted by several researches, however, that road profiles are generally nonstationary signals that contain significant transient events and are not well described in the spectral domain. The objective of this work, then, is to develop a method by which the characteristics of the road can be captured by describing these constitutive transient events.

The effects of vehicle “stiffness” and mass on the occupant response during a crash may be determined by evaluation of accident data. However, “stiffness” and mass may be correlated, making it difficult to separate their effects. In addition, a single-valued “stiffness”, although well defined for linear case, is not well defined for non-linear systems, such as in vehicle crash, making the separation task even more difficult. One approach to addressing the lack of a clear definition of stiffness is to use multiple definitions. Each stiffness definition can then be correlated with mass to look for trends. In this study, such an approach was taken, and the different stiffness definitions were given and their values were obtained from rigid barrier crash test data. No clear relationship between mass and stiffness appears to exist. All the stiffness measures reviewed show, at best, only a weak correlation with mass. A stiffness analysis among different vehicle types was also carried out.

Loads generated during assembly may cause significant stress levels in components. Under test conditions, these stresses alter the mean stress which in turn, alters the fatigue life and critical stress area of the components as well. This paper describes the Finite Element Analysis (FEA) procedure to evaluate behavior of a cast aluminum wheel subjected to the rotary fatigue test condition as specified in the SAE test procedure (SAE J328 JUN94). Fatigue life of the wheel is determined using the S-N approach for a constant reversed loading condition. In addition, fatigue life predictions with and without clamp loads are compared. It is concluded that the inclusion of clamp load is necessary for better prediction of the critical stress areas and fatigue life of the wheel.

Once the design of a door sheetmetal and accessories is confirmed, the acoustics of the door system depends on the sound package assembly. This essentially consists of a watershield which acts as a barrier and a porous material which acts as an absorber. The acoustical performance of the watershield and the reverberant sound build-up in the door cavity control the performance. This paper discusses the findings of a design study that was developed based on design of experiments (DOE) concepts to determine which parameters of the door sound package assembly are important to the door acoustics. The study was based on conducting a minimum number of tests on a five factor - two level design that covered over 16 different design configurations. In addition, other measurements were made that aided in developing a SEA model which is also compared with the findings of the results of the design study.

In the automotive industry, in order to characterize and evaluate damping treatments, it is a common practice to employ Oberst bar tests as specified by ASTM E756 and SAE J1637. The ASTM standard provides equations for sandwiched Oberst bars. These equations allow engineers to extract the properties of the visco-elastic core. For certain type of automotive constrained-layer damping treatments, such as the Aluminum Foilback, it is often convenient and desirable to prepare the Oberst bar samples with production-intent configuration. Unfortunately, these configurations are often asymmetric. Therefore, the composite Oberst bar data cannot be post-processed by employing the ASTM equations. In this study, the ASTM equations for sandwiched bars are modified to accommodate for asymmetric Oberst bar configurations. The finite element method is used to validate the derived equations by performing a “Virtual Oberst Bar test.”

Typical automotive sound package components are usually characterized by their absorption coefficients and their acoustic power-based insertion loss. This insertion loss (IL) is usually obtained by subtracting the transmission loss (TL) of a bare flat steel plate from the TL of the same plate covered with the trim material. While providing useful information regarding the performance of the component, air-borne insertion loss is based solely on acoustic excitations and thus provides very little information about the structure-borne performance of the component. This paper presents an attempt to introduce a standard procedure to define the power-based structure-borne insertion loss of sound package components. A flat steel plate is excited mechanically using a shaker. Different carpet constructions are applied on the plate and tested. Based on velocity measurements, a force transducer and intensity probe, the mechanical input and the acoustic radiated power are obtained.

Laminated steel sheets sandwiched with a polymer core are increasingly used for automotive applications due to their vibration and sound damping properties. However, it has become a major challenge in finite element modeling of laminated steel structures and forming processes due to the extremely large differences in mechanical properties and in the gauges of the polymer core and the steel skins. In this study, circular cup deep drawing and V-bending experiments using laminated steels were conducted in order to develop a modeling technique for laminate forming processes. The effectiveness of several finite element modeling techniques was investigated using the commercial FEM code LS-Dyna. Furthermore, two production parts were selected to verify the modeling techniques in real world applications.

One way to improve vehicle's fuel economy is to reduce its weight. Reducing weight, however has other consequences. One of these is reduced vehicle size. Almost invariably, lighter vehicles are smaller. Reducing vehicle weight has also been associated with a reduction in occupant protection; the lighter the vehicle, the greater the chance of injury when a crash occurs. For this study, a data-based model is used to evaluate the independent effects of size and weight. This model is constructed using the NASS database and information obtained from NCAP tests. The results indicate that although mass is the dominant factor, size also has an effect; some of the observed reduction in safety benefits associated with mass reduction is actually an effect of size reduction. The model is also used to evaluate the effects of varying stiffness.

A new multi-layer co-extruded in-color Ionomer film is developed to provide an alternative decoration process to replace paint on Dodge Neon Fascias. The Ionomer film provides a high-gloss “class-A” surface in both non-metallic and metallic colors that match the car body paint finish. Using the Ionomer film to decorate fascias reduces cost; eliminates VOCs; increases manufacturing flexibility and improves performance (weatherability and durability). The molding process consists of thermoforming a film blank and injection molding Polypropylene or TPO behind the film. The paper will include the background, the benefits, the technology development objectives, the film materials development, tooling optimization, film fascia processing (co-extrusion; thermoforming and injection molding) and validation testing of the film.

Vehicle design and packaging is a repetitive and tedious process that involves frequent engineering and design changes. To improve design efficiency, a standard naming vehicle design methodology is proposed in this paper. For the geometric or the functional object used in the vehicle context, a standard name is assigned and also used as a unique object feature through its life cycle. With the proposed standard naming design methodology, the engineering knowledge can be efficiently embedded into the CAD design, and hence, vehicle design can be executed in a more automated fashion. Work case of the standard naming design methodology is illustrated by a vehicle design and packaging application using CATIA V5.

This paper contains a review of methods for deriving risk curves from biomechanical data obtained from impact experiments on human surrogates. It covers many of the problems and pitfalls of obtaining realistic human risk curves from impact experiments. The strength and weakness of both parametric and non-parametric methods are evaluated. The limitations of standard analysis of censored impact test data are presented. Methods are given for determining risk curves from both doubly censored data and data obtained from impacts to body regions in which there are more than one mechanism of injury. A detailed set of examples is presented in which different experimental data are analyzed using the Consistent Threshold method and the logistic approach. Finally risk curves for published data are presented for the femur, head, thorax, and neck.

This paper deals with the effects of various approaches for modeling of strain rate effects for mild and high strength steels (HSS) on impact simulations. The material modeling is discussed in the context of the finite element method (FEM) modeling of progressive crush of energy absorbing automotive components. The characteristics of piecewise linear plasticity strain rate dependent material model are analyzed and various submodels for modeling of impact response of steel structures are investigated. The paper reports on the ranges of strains and strain rates that are calculated in typical FEM models for tube crush and their dependence on the material modeling approaches employed. The models are compared to the experimental results from drop tower tests.

The Automotive Industry/Government Emissions Research CRADA (AIGER) has been working to develop a new methodology for the direct determination of nonmethane hydrocarbons (DNMHC) in vehicle testing. This new measurement technique avoids the need for subtraction of a separately determined methane value from the total hydrocarbon measurement as is presently required by the Code of Federal Regulations. This paper will cover the historical aspects of the development program, which was initiated in 1993 and concluded in 2002. A fast, gas chromatographic (GC) column technology was selected and developed for the measurement of the nonmethane hydrocarbons directly, without any interference or correction being caused by the co-presence of sample methane. This new methodology chromatographically separates the methane from the nonmethane hydrocarbons, and then measures both the methane and the backflushed, total nonmethane hydrocarbons using standard flame ionization detection (FID).

As the standards for exhaust emissions have become more stringent, the quality control tools used to evaluate the performance of low level samplers and analyzers has become more important. The Vehicle Exhaust Emissions Simulator (VEES) was developed to evaluate the performance of vehicle or engine exhaust emissions sampling and analytical systems. The simulator emulates emissions from low-emitting gasoline vehicles by producing a simulated exhaust stream containing emission constituents (HC, CO, CO2, and NOx) injected via Mass Flow Controllers (MFCs). This paper discusses various applications of the VEES as a quality control tool for ULEV and SULEV testing. A comparison is made between the injected amount of exhaust species by the VEES and the amounts recovered by the different sampling systems. Different root cause scenarios are discussed as to the source of discrepancies between the results on the CVS and BMD for different driving cycles.

Most products are designed to operate for a long period of time, and in such case, life testing is a relatively lengthy procedure. Lengthy tests tend to be expensive and the results become available too late to be of much use. To reduce the experimental cost significantly and provide an efficient tool to assess the life distribution for highly reliable product, a step-stress accelerated test (SSAT) was developed. An example of a rear suspension aft lateral link is used to validate the SSAT method.