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Thermal Management Systems Symposium industry discusses latest regulatory impacts, applications to reduce engine emissions, conserve energy, reduce noise, improve the cabin environment, increase overall vehicle performance passenger, commercial vehicle industry.

This paper describes the application of statistical techniques related to the condensation of computational models so that gradient based optimization procedures can be used more effectively. The adoption of these techniques is encouraged by the possibility of an important reduction in time and cost associated to the vehicle development process. A sophisticated computational model of a Mini-baja vehicle is defined in the virtual environment by means of CAD/CAE software, intending to provide the major information related to the study of its dynamic behaviour and to define the statistical surrogates (approximate models). The creation of the computational model deals with the determination of physical and geometric properties, and is fed by stiffness and damping parameters obtained through experimental procedures.

The paper describes a detailed mathematical analysis of the problem of jet mixing in swirling or transverse flow fields under non-isothermal, non-isodense conditions. The model takes into account potential core effects, cross sectional distortion and differences in profiles between the distributed properties (velocity, concentration, temperature and density). Comparisons with a wide range of experimental results have produced excellent agreement.

A Computer Aided System (CAS) is developed in order to evaluate off-road wheeled vehicle mobility. The system takes into consideration both vehicle technical parameters and the main specifications of the soil on which the vehicle is expected to operate. Thirty seven vehicle technical parameters organized in nine groups are considered. These groups are: weights, engine parameters, dimensions, performance, transmission, steering, brakes, tires, and self recovery means. The main soil specifications of the soil considered are the soil type (clay, silt, or sand) and the shear and bearing resistance represented by the cone index or the gradient cone index. The evaluation process depends on considering a datum value for each vehicle technical parameter. These datum values or norms are obtained from a statistical analysis study of the technical parameters for a sample of 155 off-road wheeled vehicles representing different schools from all over the world [1].

The need for a foreshortened product development lead time has become a necessity, in today's economy, to the efficient manufacturing of off-highway mining trucks. This paper reviews the approach taken by one noted truck manufacturer. By utilizing finite element analysis, plastic scale modeling techniques, and a comprehensive full scale test facility, the development lead time of the WABCO 100 Ton HAULPAK* was reduced to 60% of that normally required for the development of a new product from conceptual layout to production release.

Heavy commercial vehicle axle shafts are designed for torsion load. Typically, axle shaft fracture mode during the test is torsional in nature through either shaft body diameter or spline end. However, some of the field return axles shows fracture mode on axle shaft flange. This fracture mode does not resemble with a typical lab test torsional fracture. Metallurgical investigation report indicated that the fracture mode is bending in nature. This paper thus focuses on detail study of change in boundary condition and load transfer path under abusive vertical bending load on axle. A detail finite element analysis is performed to understand stress state change in axle shaft under this condition. A fracture hypothesis is proposed based on observations of finite element analysis results. A detail case study is presented depicting correlation of proposed hypothesis with physical fracture mode.

Adjuster rings are used in commercial vehicle axle assembly to preload differential bearings and provide support in the axial direction. Adjuster along with the carrier and bearing cap combined to form a threaded joint. Adjuster with external threads engages with internal threads formed in carrier and bearing cap. Preload in differential assembly maintains the system rigidity and helps to maintain an optimized hypoid gear engagement. An adequate preload is important to achieve a desirable bearing life. Reduction in thread engagement at adjuster joint fully or partially will cause a reduction in preload and can lead to gear misalignment. This can cause severe durability concerns. In some cases, it is observed that under vehicle operating loads adjuster ring is backed off from its assembled condition by bending the split pin (split pin is, positive lock, used to maintain adjuster position) and adjuster threads were stripped off.

Pinion bearing loads of a heavy duty rear truck axle were determined by Finite Element Method Analysis (FEM). The results were compared with measured loads. This report describes the method used to measure bearing loads, the FEM model used, and the comparison of the results.

The rollover threshold for a partially filled tanker truck carrying fluid cargo is of great importance due to the catastrophic nature of accidents involving such vehicles, particularly when payloads are toxic and flammable. In this paper, a method for determining the threshold of rollover stability of a specific tanker truck is presented using finite element analysis methods. This approach allows the consideration of many variables which had not been fully incorporated in past models, including nonlinear spring behavior and tank flexibility. The program uses simple mechanical pendulums to simulate the fluid sloshing affects, beam elements to match the torsional and bending stiffness of the tank, and spring damper elements to simulate the suspension. The finite element model of the tanker truck has been validated using data taken by the U.S. Army Aberdeen Test Center (ATC) on a M916A1 tractor/ Etnyre model 60PRS 6000 gallon trailer combination.

In this study the finite element method is used to simulate a light truck multi-leaf spring system and its interaction with a driven axle, u-bolts, and interface brackets. In the first part of the study, a detailed 3-D FE model is statically loaded by fastener pre-tension to determine stress, strain, and contact pressure. The FE results are then compared and correlated to both strain gage and interface pressure measurements from vehicle hardware test. Irregular contact conditions between the axle seat and leaf spring are investigated using a design of experiments (DOE) approach for both convex and discrete step geometries. In the second part of the study, the system FE model is loaded by both fastener pre-tension and external wheel end loads in order to obtain the twist motion response. Torsional deflection, slip onset, and subsequent slip motion at the critical contact plane are calculated as a function of external load over a range of Coulomb friction coefficients.

In this paper, we explain the process of designing fuzzy based analyzers which can be installed in a vehicle. These analyzers use some kinds of sensors to detect the driver fatigue. This system helps a driver to be alert during vehicle driving. We propose a fatigue detection method which works in different way from the previous systems. In this method using some tactile sensors, the system predicts fatigue before the driver falls asleep, while driver's alertness and reaction decreases and the probability of the accident increases. An alarm massage concentrates the driver attention while s/he is going to be fallen in sleep. An advantage of this kind of fatigue detection is that it doesn't interfere with the driver's habit in vehicle control and it resumes functioning only in critical moments.

The reproduction of the vehicle motion is a crucial element of accident reconstruction. Apart from the position of the center of gravity in an inertial coordinate system, the vehicle heading plays an important role. The heading is the sum of the yaw angle and the vehicle body side slip angle. In standard vehicles, the yaw angle can be determined using the yaw rate sensor and the wheel speeds. However, the yaw rate sensor is often subject to temperature drift. The wheel speed signals are forged at low speeds or due to slip. These errors result in significant deviations of reconstructed and real vehicle heading. Therefore, an intelligent combination of these signals is required. This paper describes a fuzzy system which is capable to increase the accuracy of yaw angle calculation by means of fuzzy logic. Before the data is applied to the fuzzy system, it is preprocessed to ensure the accuracy of the fuzzy system inputs.

Abstract Performing an uncertainty analysis for complex measurement tasks, such as those found in engine research, presents unique challenges. Also, because of the excessive computational costs, modeling-based approaches, such as a Monte Carlo approach, may not be practical. This work provides a traditional statistical approach to uncertainty analysis that incorporates the uncertainty tree, which is a graphical tool for complex uncertainty analysis. Approaches to calculate the required sensitivities are discussed, including issues associated with numerical differentiation, numerical integration, and post-processing. Trimming of the uncertainty tree to remove insignificant contributions is discussed. The article concludes with a best practices guide in the Appendix to uncertainty propagation in experimental engine combustion post-processing, which includes suggested post-processing techniques and down-selected functional relationships for uncertainty propagation.

A method to achieve roll-off cleanliness has been in existence since November 1979. This paper reviews the application of the procedure in one manufacturers operation and establishes additional considerations which should be given. A method of statistical analysis of shipaway cleanliness is employed to demonstrate capability.

The goal of this study was to determine the design constraints for the Georgia Southern SAE BAJA vehicle to operate in a rough terrain without unwanted direct body impact. The BAJA vehicle may encounter two distinct kinds of failure while climbing or descending terrain obstacles: Hang up failure, and Nose in failure. Hang up failure occurs when the bottom of the chassis of the vehicle makes contact with the obstacle. This occurs after the front tires have cleared the obstacle but before the rear tires have. This mitigates the pace of the vehicle but does not structurally threaten it. Nose in failure is when the protruding front bumper or “nose” of the vehicle makes contact with either the ground or the obstacle before or after encountering the obstacle. The possible ramifications of this event are much more disastrous than the Hang up failure. Nose in failure can send the vehicle into an end over end flip, or cause significant structural damage to the frame.

In an effort to reduce the design cycle time and to meet increasingly demanding applications, an improved procedure for bearing retainer design has been introduced. This paper discusses a methodology which allows the designer to predict the life and failure modes of a retainer under application conditions. Specific attention is given to the case of fatigue of the retainer due to the dynamic interactions between the retainer, rolling elements and races. The methodology which has been developed for the life prediction of retainers is based on the dynamic loads and retainer structural integrity. Central to this technique is the ability to predict the loads imposed on the retainer as a function of design and application conditions. The bearing analysis code ADORE has been used for this purpose. The technique will be discussed by means of an example.

The commercial vehicle industry is evolving faster with the rise in multifarious aspects deciding a company's progress. In the current scenario, vehicle performance and its reliability in the areas of payload, fuel economy, etc. play vital roles in determining its sustenance in the industry, in addition to reducing driver fatigue and improving comfort levels. Test quality and time is the key to assure and affirm, smooth and quick launch of the product into the market. This paper details on the design of Multi-Axis road data simulator which entails realistic loads onto the components for capturing meaningful information on behavior of the product and recreate the field failure modes. The design was conceptualized keeping in mind both cost (for initial installation and running cost) and time for testing without loss in the convergence factor.

A new cost-reduced generation (C-Version) of ABS with integral drive slip control, so-called Anti-wheel Spin Regulation (ASR) or Automatic Traction Control (ATC) for trucks and buses has been developed for the different requirements and standards of the world market and also especially for US vehicles. The system is based on field experiences with Anti-Lock Braking System (ABS) for commercial vehicles in Europe, North America and Japan as well as with integrated ASR. This paper describes the modular system configurations and components some new features and control modes. New engine controls are realized with a new pneumatic servo valve or via a data link according to SAE-standard J 1708/1922 for the US-market. In addition the paper deals with the technology and lay-out of the new ECU, its EMC, failure detection and failure mode principles, diagnostic means according to the standards ISO 9141 or SAE J 1708/1587, as well as a dedicated blink-code.

This paper describes method which experimentally reproduces the most prevalent bearing fatigue failure modes experienced in ball and roller bearing applications. Generally, bearing fatigue life is divided into two groups. One is a surface-originating type of fatigue. The other is a subsurface-originating type of fatigue. The mechanism of each type of fatigue has been studied. Bearing materials were developed for long-life based on the study of the mechanism of fatigue. However, the condition of the evaluation method, or life test, may be different from the actual application conditions. For instance, the subsurface-originating type of fatigue is tested under extremely heavy loads. The surface-originating type of fatigue is tested with severely contaminated lubrication. There is the possibility that the evaluation methods do not simulate the failure modes that are actually present in the field.