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Steering Wheel Torsional Vibration (SWTV) at highway speed on smooth roads is one important attribute affecting vehicle refinement. To ensure desirable SWTV performance, achieve the best design compromises and minimize the development cost, specific design targets need to be defined and the proposed design needs to be assessed very early in the vehicle development cycle. In this paper, the fundamental dynamics of SWTV are analyzed and examples are given to demonstrate the strategies to reduce the SWTV response. Influence of design parameters on the SWTV response is predicted for four vehicle platforms. General guidelines for designing suspension and steering systems are discussed to ensure achieving SWTV targets.

In order to provide a correct aerodynamic simulation of a vehicle traveling along the ground, models are tested using rotating wheels in a wind tunnel with a moving ground. In the most common of configurations the model is supported by a vertical strut, usually designed as an aerofoil profile to minimize interference, with the wheels supported by lateral arms hinged to mounts outside the span of the moving ground plane. In using this type of configuration it is assumed that the presence of the intruding supports do not markedly affect the aerodynamic behavior of the model but this assumption is not always valid. In order to quantify interference effects from support struts, several models were tested over a stationary ground plane mounted to an under floor balance. Each model was tested with and without mock struts, which do not actually support the model.

Rolling road testing at model scale is most often done using a wide-belt to provide a good simulation of the relative movement between the vehicle and the road. This generally requires the use of struts to hold the model under test in position, and the aerodynamic interference of these struts can be significant. A non-intrusive method of model testing would therefore be desirable. Many alternatives for reducing or eliminating the strut interference have been considered; of these magnetic levitation has been identified as the approach with the greatest ultimate potential. Previous attempts at magnetic levitation within the aerospace community have been restricted to small scale due to the large magnetic air gap required between the model and the tunnel walls. For ground vehicles, however, the gap between the underside of the model and the tunnel floor is relatively small, providing an opportunity for magnetic levitation on a practical scale.

Halogen light sources for automotive forward lighting applications are designed for a nominal DC voltage and power, typically in the range of 13 volts and 55 to 65 watts. However some applications attempt multifunctional use, such as a high beam – day time running lamp (DRL) combination, by regulating the power. This can be done by pulse width modulation (PWM) or by simply lowering the applied DC voltage. More advanced applications, such as smart headlamps or advanced forward lighting systems, might also operate the bulb only for a short period of time. This can have a similar effect as PWM. In either case the halogen bulb will perform differently than at the DC design voltage. The valid power or voltage ranges do not only depend on the light source itself, but strongly on environmental conditions. Thermal management and external temperatures of the system can influence or prevent the halogen cycle activation and cause problems, such as bulb wall blackening.

This paper describes an effective method of developing a soundproof package, which balances both light weight and high noise insulation performance. Since it is required to propose design of sound insulator in the early stages of the development, the hybrid statistical energy analysis (SEA) modeling method is applied, which is practical for high frequency analysis. Also an acoustic characteristic estimation technique of the multi layer structures is used. As a result of applying these effective methods, the 2006 brand-new vehicle categorized as C has enhanced in road noise quietness and decreased in weight as compared with the previous model.

The increasing demands to reduce cost is forcing North American Automotive designers towards finding ways to use the thermoplastic material for the under hood components. The use of this material has often been avoided in this type of applications due to concerns around its long-term strength and temperature performance. In particular, the materials of choice for the engine cam cover are Aluminum, Magnesium and Vinyl Ester (Thermoset) although thermoplastic is widely used in Europe and Asia. This paper examines the potential of a thermoplastic cam cover designed to replace the thermoset cam cover in a 4.0L SOHC V6 engine. Experimental data, presented in this paper, demonstrate that a well-designed thermoplastic cam cover can achieve key functional requirements, such as NVH and sealing, while providing substantial cost saving.

The main objective of this paper was to determine if the vehicle performance can be maintained with a reduced mass cradle structure. Aluminum and magnesium cradles were compared with the baseline steel cradle. First, the steel chassis alone is analyzed with the refined finite element model and validated with experimental test data for the frequencies, normal modes, stiffnesses and the drive-point mobilities at various attachment mount/bushing locations. The superelement method in conjunction with the component mode synthesis (CMS) technique was used for each component of the vehicle such as Body-In-White, Instrument Panel, Steering Column Housing & Wheel, Seats, Cradles, CRFM, etc. After assemblage of all the superelements, analysis was carried out by changing the front and rear cradle gauges and the material properties. The drive-point mobility response was computed at various locations and the noise (sound pressure) level was calculated at the driver and passenger ears.

This paper discusses the development of lighter weight, superior acoustic performance and cost effective viscoelastic microcellular foams for the use in automotive passive noise control panels. The study incorporates the control of the foaming process for production of variable microcellular structures and morphologies for the novel foams under investigation. For that purpose, the foaming process was controlled for production of foam samples with various microcellular structures. Cross linked LDPE was used as a base material for the produced foams. Very high open-cell content (ranging between 43 - 95%), high microcellular cell densities (9E108 - 1.6E109 cells/cm3) and desired expansion ratios (3 - 9 folds) were successfully obtained. While the material is overly porous, it is noted that the unfoamed skins on the outer surfaces of the samples have prevented sound waves from penetrating the samples. Manual skin removal resulted in slight improvement in sound absorption testing.

Advances in the design and manufacturing of Expandable Epoxy Foam Inserts have resulted in a dramatic rise in the use of these technologies for the treatment of structureborne noise and vibration control. The evolution of these technologies has resulted in light weight and cost competitive solutions when compared to changes in primary body structure and surrounding sheet metal. These advances are discussed in detail. A structured, methodical approach to the identification of requirements for vehicle treatments is discussed. Based on these requirements, a process for the evaluation of application designs and the design optimization process are discussed. Validation of both the material technology and the engineering approach are presented through demonstration on actual vehicle applications.

In recent years, automotive engine manufacturers are increasingly focusing their attention on noise generated by plastic air intake manifolds (AIMs). Due to their lower density and stiffness, some deficiencies in terms of acoustical properties have been observed for plastic intake systems compared to metallic manifolds. In this framework, it seems to be very important to address not only the issue of reducing inlet noise, but also noise radiated via the coupled fluid-structure interaction. In this work three AIMs, a baseline and two modified models, nominally having equal breathing performance, have been analyzed and compared. The modified ones presented ribs and stays for strengthening the structure. The analyses were performed with concurrent experimental and numerical validated procedures.

As noise and vibration are constantly being evaluated and targeted for improvement in automotive engineering, it is important to understand the performance capabilities of the materials used in transmission shift cable systems to reduce noise, vibration, and harshness (NVH). Energy absorbing materials are commonly used in push-pull cable systems for isolating terminal attachments and conduit abutments. Integrated into the cable system, these materials isolate the vehicle's shift mechanism from its external attachments at the transmission. When sufficient heat and load are applied in cycles, these materials will deform over time. As the components deform in shape there is a reduction in a shift system's ability to transmit motion.

Un-dispersed antifreeze can cause detrimental changes in diesel engine oils. The oil condition sensor invented at Delphi Corporation can detect un-dispersed antifreeze in diesel and gasoline engine oils. Un-dispersed antifreeze appears as a separate phase and settles at the bottom of oil pans. In order to detect un-dispersed antifreeze, the sensor has to be mounted at the bottom of oil pans. A new technique, which analyzes the minor changes of gasoline engine oil resistance, was developed earlier to detect antifreeze leakage in gasoline engine oil before the phase separation. With this add-on feature, the oil condition sensors no longer have to be mounted at the bottom of gasoline oil pans. In this work, we extend this technique and verify its feasibility in diesel engine oils. At 35°C, the detection limits for this technique vary from 0.13 to 0.25% of antifreeze in diesel engine oils.

Posture selection during standing exertions is a complex process involving tradeoffs between muscle strength and balance. Bodyweight utilization reduces the amount of upper-body strength required to perform a high force push/pull exertion but shifts the center-of-gravity towards the limits of the functional stability region. Thus balance constraints limit the extent to which bodyweight can be used to generate push/pull forces. This paper examines a two-handed sagittal plane pulling exertion performed during a battery maintenance task on a member of the family of medium-sized tactical vehicles (FMTV). Percent capable strength predictions and functional balance capabilities were determined for various two-handed pulling postures using the University of Michigan's 3D Static Strength Prediction Program (3DSSPP). Through this simulation study, preferred postures that minimize joint torques while maintaining balance were identified.

This paper presents new capabilities of the virtual-human Santos™ introduced last year. Santos™ is an avatar that has extensive modeling and simulation features. It is a digital human model with over 100 degrees-of-freedom (DOF), where the hand model has 25 DOF, direct optimization-based method, and real-human like appearance. The newly developed analysis includes (1) a 25-DOF hand model that is the first step to study hand grasping; (2) posture prediction advances such as multiple end-effectors (two arms, two arms + head + legs), real-time inverse kinematics for posture prediction for any points, vision functionality; (3) dynamic motion prediction with external loads; and (4) musculosteletal modeling that includes determining muscle forces, and muscle stress.

Compact heat exchangers have been widely used in various applications in thermal fluid systems including automotive thermal management systems. Radiators for engine cooling systems, evaporators and condensers for HVAC systems, oil coolers, and intercoolers are typical examples of the compact heat exchangers that can be found in ground vehicles. Among the different types of heat exchangers for engine cooling applications, cross flow compact heat exchangers with louvered fins are of special interest because of their higher heat rejection capability with the lower flow resistance. In this study, a predictive numerical model for the cross flow type heat exchanger with louvered fins has been developed based on the thermal resistance concept and the finite difference method in order to provide a design and development tool for the heat exchanger. The model was validated with the experimental data from an engine cooling radiator.

Due to coming more stringent legislation regarding emission of diesel engines, material considerations in heat exchangers will be a topic. This paper describes a method to compare the durability of tube to header joints in brazed, welded or soldered execution at ambient and elevated temperatures. Instead of pressure cycle test a complete heat exchanger only one tube to header joint is tested at a time.. This method could initially be used for selection of materials and joining methods with respect to durability. Calculations are presented to show the analogy between the described test method and internal pressure pulsation. Examples of measured results are presented. By combining different tube and braze filler materials comparing studies can be done.

A two-dimensional analytical model is developed by solving the differential equations which describe the motion of a vehicle in laboratory-based rollover events. The model is based on a rigid-body kinematics assumption for the entire vehicle. Three cases are studied: the first case deals with determination of the Critical Sliding Velocity of a vehicle rolls over from a tilt table, the second case considers rollover of a vehicle which sits on a platform traveling at a velocity V which is suddenly stops, and the third one repeats the second problem except that the platform is brought to stop according to a given deceleration profile, thus simulating the SAE J2114 rollover test procedure. For the SAE J2114 rollover test procedure simulation, the analytical results are compared with those obtained from MADYMO-based rollover model.

This paper presents an image analysis of a laboratory-based rollover crash test using camera-matching photogrammetry. The procedures pertaining to setup, analysis and data process used in this method are outlined. Vehicle roll angle and rate calculated using the method are presented and compared to the measured values obtained using a vehicle mounted angular rate sensor. Areas for improvement, accuracy determination, and vehicle kinematics analysis are discussed. This paper concludes that the photogrammetric method presented is a useful tool to extract vehicle roll angle data from test video. However, development of a robust post-processing tool for general application to crash safety analysis requires further exploration.

Federal Motor Vehicle Safety Standard (FMVSS) 208 - Occupant Crash Protection establishes performance requirements to determine whether passenger vehicles, light multipurpose vehicles, and trucks meet conditions and injury criteria specified by the standard. On May 12, 2004, the National Highway Traffic Safety Administration (NHTSA) amended the standard to set the path for future air bag development [1, 2]. The amendment concerned the development of airbag systems that would be designed to minimize the risk of air bag induced injuries in comparison to current technologies. These new rules forward the framework for engineering of these systems without strictly regulating their design. This paper will discuss the test methodologies used from the initial design phase to the final validation phase of a vehicle. Strategies for advanced air bag system types, suppression and low risk occupant mixes, and the use of human subjects will be discussed.

A prototype safety analysis system has been developed to assess and forecast vehicle safety that can assist vehicle developers integrate various safety technologies into future production vehicles. The prototype system can be used to assess the actual safety in existing vehicles based on fatal accident and vehicle registration data (e.g., US FARS and Polk data); and to estimate the safety in future vehicles based on the estimated effectiveness of candidate passive and active safety technologies (e.g., Curtain Airbags, CMBS) using a systems model with a representative sample of in-depth accident data (e.g., NASS/CDS). Therefore, the prototype system is a useful tool which can be used to estimate the net overall effectiveness of various candidate safety technologies combined, providing a metric which can be used to help optimize the effectiveness of integrated vehicle safety systems.