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Tire manufacturers have long grappled with the challenge of balancing the conflicting tire attributes of traction, rolling resistance, and treadwear. Improvements to one of these “magic triangle” attributes often comes at the expense of the other attributes. Recent regulations have further increased the pressure on manufacturers to produce optimized tires with minimal performance compromises. In order to meet this challenge, the tire industry is looking to new material systems beyond the traditional tire tread components. Polymeric materials beyond the base elastomers and processing oils used in tread provide opportunities to modify the physical and viscoelastic properties of tread. In this study, various polymeric materials were evaluated as additives in a model tire tread formulation. Hydrocarbon resin, high styrene resin, and thermoplastic styrene elastomers were added to the model formulation at various loading levels and through various addition strategies.

The measured drive-point conductance of a typical passenger car tire was seen to drop steadily for frequencies above 1000 Hz. This behavior is a-typical since SEA theory predicts such conductance should remain relatively flat for high frequencies. It was found that, one has to pay careful attention to errors introduced by the added mass of the measuring transducer and “local” effects due to contact stiffness of the tread rubber. Such effects are investigated and their contributions quantified. Compensation schemes are also developed and implemented. It is shown that, for a 20 grams transducer, the measured and corrected conductances are off by 12 dB. The effects of the local contact stiffness of the rubber at the attachment point are less significant.

During the course of emissions and fuel economy (FE) testing, vehicles that are calibrated to meet Tier 3 emissions requirements currently must demonstrate compliance on Tier 3 E10 fuel while maintaining emissions capability with Tier 2 E0 fuel used for FE label determination. Tier 3 emissions regulations prescribe lower sulfur E10 gasoline blends for the U.S. market. Tier 3 emissions test fuels specified by EPA are required to contain 9.54 volume % ethanol and 8-11 ppm sulfur content. EPA Tier 2 E0 test fuel has no ethanol and has nominal 30 ppm sulfur content. Under Tier 3 rules, Tier 2 E0 test fuel is still used to determine FE. Tier 3 calibrations can have difficulty meeting low Tier 3 emissions targets while testing with Tier 2 E0 fuel. Research has revealed that the primary cause of the high emissions is deactivation of the aftertreatment system due to sulfur accumulation on the catalysts.

A three-way catalytic converter (TWC) is an emissions control device, used to treat the exhaust gases in a gasoline engine. The conversion efficiency of the catalyst, however, drops with age or customer usage and needs to be monitored on-line to meet the on board diagnostics (OBD II) regulations. In this work, a non-intrusive catalyst monitor is developed to diagnose the track the remaining useful life of the catalyst based on measured in-vehicle signals. Using air mass and the air-fuel ratio (A/F) at the front (upstream) and rear (downstream) of the catalyst, the catalyst oxygen storage capacity is estimated. The catalyst capacity and operating exhaust temperature are used as an input features for developing a Support Vector Machine (SVM) algorithm based classifier to identify a threshold catalyst. In addition, the distance of the data points in hyperspace from the calibrated threshold plane is used to compute the remaining useful life left.

Exhaust emissions are well known to have adverse impacts on human health. Studies have demonstrated that there is an association between ambient particulate matter (PM) levels and various harmful cardiopulmonary conditions. Soot exhaust from diesel engines can be a significant contributor to airborne pollutants. A key component in PM level control for a diesel engine is a diesel particulate filter (DPF). This device traps soot while allowing other exhaust gases to pass unhindered. However, the performance of diesel particulate filters can change with increasing soot loadings and thus may require regeneration or replacement. Improved understanding of diesel particulate filters is dependent upon the knowledge of the actual soot loading and the soot distribution within the DPF. Neutron radiography (NR) has been identified as an effective means of non-destructively identifying hydrogen or carbon adsorbed in PM.

Thermally sprayed coatings have used in place of iron bore liners in recent aluminum engine blocks. The coatings are steel-based, and are sprayed on the bore wall in the liquid phase. The thermal response of the block structure determines how rapidly coatings can be applied and thus the investment and floor space required for the operation. It is critical not to overheat the block to prevent dimensional errors, metallurgical damage, and thermal stress cracks. This paper describes an innovative finite element procedure for estimating both the substrate temperature and residual stresses in the coating for the thermal spray process. Thin layers of metal at a specified temperature, corresponding to the layers deposited in successive thermal spray torch passes, are applied to the substrate model, generating a heat flux into the block. The thickness, temperature, and application speed of the layers can be varied to simulate different coating cycles.

Modern approaches for thermal fatigue damage assessment in automotive components are discussed. Three prominent methods are reviewed, and issues with related material testing, numerical implementations and applications to general thermal cycles are presented. In summary, the chosen methods can produce good thermal fatigue life predictions. Common difficulties include first, prolonged experimental programs to determine the required material parameters, and second, significant computational times involved in analysis of realistic models and loading histories.

Thermal fatigue presents a new challenge in cast aluminum engine design. Accurate thermomechanical stress analysis and reliable failure criterion are the keys to a successful life prediction. It is shown that the material stress and strain behavior of cast aluminum is strongly temperature and strain rate sensitive. A unified viscoplasticity constitutive relation is thus proposed to simultaneously describe the plasticity and creep of cast aluminum components deforming at high temperatures. A fatigue failure criterion based on a damage accumulation model is introduced. Damages due to mechanical fatigue, environmental impact and creep are accounted for. The material stress and strain model and thermal fatigue model are shown to be effective in accurately capturing features of thermal fatigue by simulating a component thermal fatigue test using 3D FEA with ABAQUS and comparing the results with measured data.

The use of nanotechnology to develop advanced heat-transfer materials is a rapidly growing topic of research at facilities around the world. One class of these materials, nanofluids, has shown promise in the laboratory to dramatically improve thermal conductivity. Quantification of the thermophysical properties of these fluids is important for optimizing the design of automotive powertrains and electrical subsystems in order to produce highly efficient and robust vehicle cooling. A new technique for measuring thermal conductivity, the Transient Planar Source (TPS) method, was used for the first time to investigate the thermal conductivity of automotive coolants and their equivalent nanofluid, as a function of temperature. The results of this study indicate that the TPS method allows for rapid and repeatable measurement of thermal conductivity with an error of between 2-4%. The technique also presents several advantages over other methods which we will briefly describe.

The purpose of this paper is to construct the thermal analysis model by measuring and estimating the temperature at the traction contact area. For measurement of temperature, we have used a thin-film temperature sensor. For estimation of temperature, we have composed the thermal analysis model. The thin-film temperature sensor was formed on the contact surface using a spattering device. The sensor is constituted of three layers (sensor layer, insulation layer and intermediate layer). Dimensions of the sensor were sufficiently smaller than the traction contact area. The sensor featured high specific pressure capacity and high speed responsiveness. The thermal analysis model was mainly composed of three equations: Carslaw & Jaeger equation, Rashid & Seireg equation and heat transfer equation of shear heating in oil film. The heat transfer equation involved two models (local shear heating model at middle plane, homogeneous shear heating model).

On current competitive scenario for road load transportation in Brazilian market, the operational costs should be reduced as much as possible. The suspension system commonly used on road commercial trucks is based on leaf spring use and Hotchkiss concept for axle locating devices. The use of leaf springs without bolt attachment eyelets are still common for rear suspension systems. When using the leaf spring with direct contact to the brackets, wear plates are placed between them to work as wear elements due to the friction between the parts. The friction will cause wear on the parts, and the wear plate is designed to suffer the damages of this friction instead of the leaf spring, being the cheapest element and can be easily replaced. When the system works on a severe contamination environment with high levels of grit and dirt, the degradation of the parts are accelerated.

In an evaluation of crashworthiness for the cars made of aluminum alloys, the evaluation considering fracture phenomenon comes to be needed because conventional aluminum alloys have low fracture strain (10-20%). In case of the development of a B-Pillar made by die cast, if crack occurrence, furthermore, separation of a part can be estimated by using CAE in crashworthiness evaluations, we can reduce the number of prototype makings and the cost of development using expensive dies. Therefore, we performed crashworthiness evaluations by CAE using some sort of a damage & fracture material model. It is known as “Orthotropic damage & fracture model”.

Wavelets are a powerful mathematical tool used to multi-resolution time-frequency decomposition of signals, in order to analyze them in different scales and obtain different aspects of the information. Despite being a relatively new tool, wavelets have being applied in several areas of human knowledge, especially in signal processing, with emphasis in encoding and compression of image, video and audio. Based on a previous successful applications (FRAZIER, 1999) together a commitment to quality results, this paper evaluates the use of the Discrete Wavelet Transform (DWT) as an compression algorithm to reduce the amount of data collected in road load signals (load history) which are used by the durability engineering teams in the automotive industry.

Over the past five years, the US Automotive Materials Partnership (USAMP) has brought together representatives from DaimlerChrysler, General Motors, Ford Motor Company and over 40 other participant companies from the Mg casting industry to create and test a low-cost, Mg-alloy engine that would achieve a 15 - 20 % Mg component weight savings with no compromise in performance or durability. The block, oil pan, and front cover were redesigned to take advantage of the properties of both high-pressure die cast (HPDC) and sand cast Mg creep- resistant alloys. This paper describes the alloy selection process and the casting and testing of these new Mg-variant components. This paper will also examine the lessons learned and implications of this pre-competitive technology for future applications.

Historically, vehicle fluid condition has been monitored by measuring miles driven or hours operated. Many current vehicles have more sophisticated monitoring methods that use additional variables such as fuel consumption, engine temperature and engine revolutions to predict fluid condition. None of these monitoring means, however, actually measures a fluid property to determine condition, and that is about to change. New sensors and diagnostic systems are being developed that allow real time measurement of some lubricant physical and/or chemical properties and interpret the results in order to recommend oil change intervals and maximize performance. Many of these new sensors use electrochemical or acoustic wave technologies. This paper examines the use of these two technologies to determine engine oil condition and focuses on the effects of lubricant chemistry on interpreting the results.

The proliferation of Unibody construction, for vehicle weight reduction, and the expanded use of precoated steel, for improvement in outer body rust-through protection, has significantly increased the number of bimetallic and crevice unions on U.S. manufactured vehicles. Cyclic corrosion and proving ground testing has shown that these unions are highly active electrochemically, resulting in extensive anodic corrosion and cathodic de-lamination of the paint film. This work examines the individual contribution of each layer of the applied protective coatings package, with respect to applied film thickness, to the reduction of permeation by water, oxygen, and NaCl and resultant corrosion.

Recently, control of the gas-exchange process has come into focus as a critical element of the development process for internal combustion (IC) engines. The information learned in various engine development organizations worldwide has recently been put into practice via the introduction of many variable valve control strategies. The intention of these strategies ranges from simple enhancement of volumetric efficiency to completely controlling the combustion process at various engine speeds. The challenge to engine designers is mainly to reduce the relatively high masses of the valve actuating elements while increasing the stiffness to positively affect the dynamic behavior of the valve actuation system. Other benefits of a light-weight valve train is the reduction of the required energy to displace the valve element, which results in a more compact (lighter) cylinder head construction.

Pilot injection has been used widely in diesel engines for its NOx and noise reducing characteristics. In this paper, its impacts to the particle emissions were studied using a light-duty common-rail Euro 4 diesel engine with different pilot injection strategies. Three steady-state engine modes were selected from the EU legislative diesel engine test cycle to represent low, medium and high engine speeds and loads. The quantities and injection timings of the pilot injection strategies were then varied. The particle number concentration and size distributions were investigated along with the smoke and regulated gas emissions such as the NOx trade-off. These results indicate how a pilot injection alongside a main injection can increase the particle size compared to a single main injection event. Furthermore, the split injection was closely related to the engine mode.

The desire for greater fuel efficiency and reduced emissions have accelerated a shift from traditional materials to design solutions that more closely match materials and their properties with key applications. The Multi-Material Lightweight Vehicle (MMLV) Project presents cutting edge engineering that meets future challenges in a concept vehicle with weight and life-cycle assessment savings. These results significantly contribute to achieving fuel reduction and to meeting future Corporate Average Fuel Economy (CAFÉ) regulations without compromising vehicle performance or occupant safety.

The existence of the cyclic variation of the flow inside an cylinder affects the performance of the engine. Developing methods to understand and control in-cylinder flow has been a goal of engine designers for nearly 100 years. In this paper, passive control of the intake flow of a 3.5-liter DaimlerChrysler engine was examined using a unique optical diagnostic technique: Molecular Tagging Velocimetry (MTV), which has been developed at Michigan State University. Probability density functions (PDFs) of the normalized circulation are calculated from instantaneous planar velocity measurements to quantify gas motion within a cylinder. Emphasis of this work is examination of methods that quantify the cyclic variability of the flow. In addition, the turbulent kinetic energy (TKE) of the flow on the tumble and swirl plane is calculated and compared to the PDF circulation results.