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FutureSteelVehicle's (FSV) objective is to develop detailed design concepts for a radically different steel body structure for a compact Battery Electric Vehicle (BEV). It also will identify structure changes to accommodate larger Plug-In Hybrid (PHEV) and Fuel Cell (FCEV) vehicle variants. The presentation will demonstrate seven optimized structural sub-systems that contribute to the program's 35 percent mass reduction goals and meet its safety and life cycle emissions targets. It will explain the advanced design optimization process used and the resulting aggressive steel concepts. Presenter Jody R. Shaw, US Steel

The conventional forming limit curve (FLC) has been widely and successfully used as a failure criterion to detect localized necking in stamping. However, in stamping advanced high strength steels (AHSS), under certain circumstances such as stretching-bending over a small die radius, the sheet metal fails much earlier than predicted by the FLC. This type of failure on the die radius is commonly called “shear fracture.” In this paper, the laboratory Stretch-Forming Simulator (SFS) and the Bending under Tension (BUT) tester are used to study shear fracture occurring during both early and later stages of stamping. Results demonstrate that the occurrence of shear fracture depends on the combination of the radius-to-thickness (R/T) ratio and the tension/stretch level applied to the sheet during stretching or drawing. Based on numerous experimental results, an empirical shear fracture limit curve or criterion is obtained.

One of the issues in stamping of advanced high strength steels (AHSS) is the stretch bending fracture on a sharp radius (commonly referred to as shear fracture). Shear fracture typically occurs at a strain level below the conventional forming limit curve (FLC). Therefore it is difficult to predict in computer simulations using the FLC as the failure criterion. A modified Mohr-Coulomb (M-C) fracture criterion has been developed to predict shear fracture. The model parameters for several AHSS have been calibrated using various tests including the butter-fly shaped shear test. In this paper, validation simulations are conducted using the modified (M-C) fracture criterion for a dual phase (DP) 780 steel to predict fracture in the stretch forming simulator (SFS) test and the bending under tension (BUT) test. Various deformation fracture modes are analyzed, and the range of usability of the criterion is identified.

Quasi-static tensile properties of TRIP590 steels from three different manufacturers were investigated using digital image correlation (DIC). The focus was on the post-uniform elongation behavior which can be very different for steels of the same grade owing to different manufacturing processes. Miniature tensile specimens, cut at 0°, 45°, and 90° relative to the rolling direction, were strained to failure in an instrumented tensile stage. True stress-true strain curves were computed from digital strain gages superimposed on digital images captured from one gage section surface during tensile deformation. Microstructural phases in undeformed and fracture specimens were identified with optical microscopy using the color tint etching process. Fracture surface analyses conducted with scanning electron microscopy and energy dispersive spectroscopy were used to investigate microvoids and inclusions in all materials.

Over the last two decades, engine research was mainly focused on reducing fuel consumption in view of compliance with more stringent homologation cycles and customer expectations. As it is well known, the objective of overall engine efficiency optimization can be achieved only through the improvement of each element of the efficiency chain, of which mechanical constitutes one of the two key pillars (together with thermodynamics). In this framework, the friction reduction for each mechanical subsystem has been one of the most important topics of modern Diesel engine development. The present paper analyzes the crankshaft potential as contributor to the mechanical efficiency improvement, by investigating the synergistic impact of crankshaft design itself and oil viscosity characteristics (including new ultra-low-viscosity formulations already discussed by the author in [1]).

Gas Metal Arc Welding (GMAW) is widely employed for joining relatively thick sheet steels in automotive body-in-white structures and frames. The GMAW process is very flexible for various joint geometries and has relatively high welding speed. However, fatigue failures can occur at welded joints subjected to various types of loads. Thus, vehicle design engineers need to understand the fatigue characteristics of welded joints produced by GMAW. Currently, automotive structures employ various advanced high strength steels (AHSS) such as dual-phase (DP) and transformation-induced plasticity (TRIP) steels to produce lighter vehicle structures with improved safety performance and fuel economy, and reduced harmful emissions. Relatively thick gages of AHSS are commonly joined to conventional high strength steels and/or mild steels using GMAW in current body-in-white structures and frames.

In order to increase the efficiency of automotive turbochargers at low speed without compromising the performance at maximum boost conditions, variable geometry compressor (VGC) systems, based on either variable inlet guide vanes or variable geometry diffusers, have been recently considered as a future design option for automotive turbochargers. This work presents a modeling, analysis and optimization study for a Diesel engine equipped with a variable geometry compressor that help understand the potentials of such technology and develop control algorithms for the VGC systems,. A cycle-averaged engine system model, validated on experimental data, is used to predict the most important variables characterizing the intake and exhaust systems (i.e., mass flow rates, pressures, temperatures) and engine performance (i.e., torque, BMEP, volumetric efficiency), in steady-state and transient conditions.

Powerful vehicles that are adequately designed to corner at high speeds can generate very high lateral forces at tire-road interface. These forces are counter balanced by chassis, suspension and brake components allowing the vehicle to confidently maneuver around a corner. Although these components may not damage under such high cornering loads, elastic deflections can significantly alter a vehicles performance. One such phenomenon is increased brake pedal travel, to engage brakes, after severe cornering maneuvers. Authors of this paper have worked together to solve exactly this problem on a very powerful luxury segment car.

In practice, the piston wrist pin is either fixed to the connecting rod or floats between the connecting rod and the piston. The tribological behavior of fixed wrist pins have been studied by several researchers, however there have been few studies done on the floating wrist pin. A new bench rig has been designed and constructed to investigate the tribological behavior between floating pins and pin bore bearings. The experiments were run using both fixed pins and floating pins under the same working conditions. It was found that for fixed pins there was severe damage on the pin bore in a very short time (5 minutes) and material transfer occurs between the wrist pin and pin bore; however, for the floating pin, even after a long testing time (60 minutes) there was minimal surface damage on either the pin bore or wrist pin.

Time-averaged temperatures at critical locations on the piston of a direct-fuel injected, two-stroke, 388 cm3, research engine were measured using an infrared telemetry device. The piston temperatures were compared to data [7] of a carbureted version of the two-stroke engine, that was operated at comparable conditions. All temperatures were obtained at wide open throttle, and varying engine speeds (2000-4500 rpm, at 500 rpm intervals). The temperatures were measured in a configuration that allowed for axial heat flux to be determined through the piston. The heat flux was compared to carbureted data [8] obtained using measured piston temperatures as boundary conditions for a computer model, and solving for the heat flux. The direct-fuel-injected piston temperatures and heat fluxes were significantly higher than the carbureted piston. On the exhaust side of the piston, the direct-fuel injected piston temperatures ranged from 33-73 °C higher than the conventional carbureted piston.

In the North American automotive market, cylinder deactivation by means of engine valve deactivation is becoming a significant enabler in reducing the Brake Specific Fuel Consumption (BSFC) of large displacement engines. This allows for the continued market competitiveness of large displacement spark ignition (SI) engines that provide exceptional performance with reduced fuel consumption. As an alternative to a major engine redesign, the Active Fuel Management™ (AFM™) system is a lower cost and effective technology that provides improved fuel economy during part-load conditions. Cylinder deactivation is made possible by utilizing innovative new base engine hardware in conjunction with an advanced control system. In the GM 3.9L V-6 Over Head Valve (OHV) engine, the standard hydraulic roller lifters on the engine's right bank are replaced with deactivating hydraulic roller lifters and a manifold assembly of oil control solenoids.

Edge cracking is one of the major formability concerns in advanced high strength steel (AHSS) stamping. Although finite element analysis (FEA) together with the Forming Limit Diagram has been widely used, it has not effectively predicted edge cracking. Primary problems in developing a methodology to insure that parts are safe from edge cracking are the lack of an effective failure criterion and a simple and accurate measurement method that is not only usable in both die tryout and production but also can be verified by finite element analysis. The intent of this study is to develop a methodology to ensure that parts with internal cutouts, such as a body side panel can be produced without edge cracking. During tryout and production, edge cracking has traditionally been detected by visual examination, but this approach is not adequate for ensuring freedom from edge cracking.

A life cycle inventory (LCI) study evaluates the environmental performance of the ULSAB-AVC (UltraLight Steel Auto Body - Advanced Vehicle Concepts) vehicle product system. The LCI quantifies the inputs and outputs of each life cycle stage of the ULSAB-AVC PNGV-gas engine vehicle (998 kg) over the 193,000 km service lifetime of the vehicle. The use phase of the ULSAB-AVC PNGV-diesel engine variant (1031 kg) is also quantified. The data categories measured for each life cycle phase include resource and energy consumption, air and water pollutant emissions, and solid waste production. The ULSAB-AVC LCI study is based on the methods, model and data from the 1999 study by the United States Automotive Materials Partnership (USAMP), a consortium within the United States Council for Automotive Research. This model was modified to represent the ULSAB-AVC PNGV-gas engine vehicle for each life cycle phase as well as the use phase of the PNGV-diesel engine variant.

A new Diesel engine, called the Duramax 6600 (Fig.1), has been designed by Isuzu Motors (Isuzu) for an upcoming full-size General Motors (GM) pickup truck. It incorporates the latest Diesel technology in order to improve on the inherent strengths of a Diesel engine, such as fuel economy, torque and reliability, while also producing higher output, smoother driveability, and lower noise. The Duramax 6600 is an entirely new 90° V8 direct injection (DI) intercooled engine with a water-cooled turbocharger. Its fuel injection system employs a fully electronically controlled common rail system that has high-pressure injection capabilities. Isuzu had the design responsibility of the base engine, while GM Truck Group was responsible for designing the installation and packaging within the vehicle. Engine validation relied on Isuzu's proven validation process, in addition to GM Powertrain's expertise in engine validation.

A compact, lightweight compression-ignition engine designed for high fuel economy and low emissions was developed by ISUZU for the GM PNGV vehicle. This engine was the key component in the selected parallel hybrid vehicle powertrain for the 80 mpg fuel economy target. The base hardware was derived from a 1.7 Liter, 4-cylinder engine, and a three-cylinder version was created for the PNGV application. To achieve the required high efficiency, the engine used lightweight components thus minimizing weight and friction. To reduce exhaust emissions, electromechanical actuators were used for EGR, intake throttle, and turbocharger. Through careful application of these devices and combustion development, stringent engine out exhaust emission targets were also met.

The Auto/Steel Partnership Corrosion Project Team has completed a perforation corrosion test program consisting of on-vehicle field exposures and various accelerated tests. Steel sheet products with eight combinations of metallic and organic coatings were tested, utilizing a simple crevice coupon design. On-vehicle exposures were conducted in St. John's and Detroit for up to seven years to establish a real-world performance standard. Identical test specimens were exposed to the various accelerated tests, and the results were compared to the real-world standard. This report documents the results of these tests, and compares the accelerated test results (including SAE J2334, GM9540P, Ford APGE, CCT-I, ASTM B117, South Florida Modified Volvo, and Kure Beach (25-meter) exposures) to the on-vehicle tests. The results are compared in terms of five criteria: extent of corrosion, rank order of material performance, degree of correlation, acceleration factor, and control of test environment.

The Austempering heat treatment is a well-known solution to improve the mechanical properties of ductile cast irons, therefore being referred as 'ADI' (Austempered Ductile Iron). The improved mechanical properties of ADI's with respect to conventional ductile iron is attributed to its resulting microstructure, which contains mainly carbide-free bainite with stabilized retained austenite. More recently, ductile cast irons were submitted to another heat treatment, known as 'Quenching and Partitioning' (Q&P). In this case, the ductile cast iron is austenitized, quenched to a temperature between Mf and Ms temperatures and subsequently heated to a temperature above Ms in order to partition the carbon from the martensite to the remaining austenite. The resulting microstructure comprises mainly low carbon martensite, austenite (stabilized by the carbon partition) and carbide-free bainite. Such microstructure resulted in equal or better properties than ADI.

In this work, an experimental and analysis methodology was developed to evaluate the preignition propensity of fuels and engine operating conditions in an SI engine. A heated glow plug was introduced into the combustion chamber to induce early propagating flames. As the temperature of the glowplug varied, both the fraction of cycles experiencing these early flames and the phasing of this combustion in the engine cycle varied. A statistical methodology for assigning a single-value to this complex behavior was developed and found to have very good repeatability. The effects of engine operating conditions and fuels were evaluated using this methodology. While this study is not directly studying the so-called stochastic preignition or low-speed preignition problem, it studies one aspect of that problem in a very controlled manner.

FutureSteelVehicle’s (FSV) objective is to develop detailed design concepts for a radically different steel body structure for a compact Battery Electric Vehicle (BEV). It also will identify structure changes to accommodate larger Plug-In Hybrid (PHEV) and Fuel Cell (FCEV) vehicle variants. The paper will demonstrate seven optimised structural sub-systems that contribute to the programme's 35 percent mass reduction goals and meet its safety and life cycle emissions targets. It will explain the advanced design optimisation process used and the resulting aggressive steel concepts.

Advanced high strength steels (AHSS) are increasingly used in automotive industry. A major issue for AHSS stamping is edge cracking. This failure mode is difficult to predict by conventional forming limit curve (FLC). The material edge stretchability is mainly evaluated using the hole expansion test. In this study, digital Image Correlation (DIC) is applied for strain measurement. DIC is a non-contact, full field, high accuracy and direct measurement technique that provides more detailed information for the evolution of strains on the sheet surface. Tests were conducted for five AHSS and nine cases. This paper will explain in detail the DIC technique and its results.