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Automotive engines are regularly utilized in the material handling market where LPG is often the primary fuel used. When compared to gasoline, the use of gaseous fuels (LPG and CNG) as well as alcohol based fuels, often result in significant increases in valve seat insert (VSI) and valve face wear. This phenomenon is widely recognized and the engine manufacturer is tasked to identify and incorporate appropriate valvetrain material and design features that can meet the ever increasing life expectations of the end-user. Alternate materials are often developed based on laboratory testing – testing that may not represent real world usage. The ultimate goal of the product engineer is to utilize accelerated lab test procedures that can be correlated to field life and field failure mechanisms, and then select appropriate materials/design features that meet the targeted life requirements.

The value of model-based design has been attempted to be communicated for more than a decade. As methods and tools have appeared and disappeared from a series of different vendors it has become apparent that no single vendor has a solution that meets all users’ needs. Recently standards (UML, MDA, MOF, EMF, etc.) have become a dominant force and an alternative to vendor-specific languages and processes. Where these standards have succeeded and vendors have failed is in the realization that they do not provide the answer, but instead provide the foundation to develop the answer. It is in the utilization of these standards and their capability to be customized that companies have achieved success. Customization has occurred to fit organizations, processes, and architectures that leverage the value of model-driven design.

As a virtual manufacturing press line, line die forming simulation provides a full range math-based engineering tool for stamping die developments of automotive structure and closure panels. Much beyond draw-die-only formability analysis that has been widely used in stamping simulation community during the last decade, the line die formability analysis allows incorporating more manufacturing requirements and resolving more potential failures before die construction and press tryout. Representing the most difficult level in formability analysis, conducting line die formability analysis of automotive body side outers exemplifies the greatest technological challenge to stamping CAE community. This paper discusses some critical issues in line die analysis of the body side outers, describes technical challenges in applications, and finally demonstrates the impact of line die forming simulation on the die development.

A DFSS study identified a new mechanism for clamp load loss in aluminum threads due to thermal cycling. In bolted joints tightened to yield, the difference in thermal expansion between the aluminum and steel threads can result in a loss of clamp load with each thermal cycle. This clamp load loss is significantly greater than the loss that can be explained by creep alone. A math model was created and used to conduct a robust analysis. This analysis led to an understanding of the design factors necessary to reduce the cyclic clamp load loss in the aluminum threads. This understanding was then used to create optimized design solutions that satisfy constraints common to powertrain applications. Estimations of clamp load loss due to thermal cycling from the math model will be presented. The estimates of the model will be compared to observed physical test data. A robust analysis, including S/N and mean effect summary will be presented.

This paper describes a vehicle-level simulation model for climate control and powertrain cooling developed and currently utilized at GM. The tool was developed in response to GM's need to speed vehicle development for HVAC and powertrain cooling to meet world-class program execution timing (18 to 24 month vehicle development cycles). At the same time the simulation tool had to complement GM's strategy to move additional engineering responsibility to its HVAC suppliers. This simulation tool called “e-Thermal” was quickly developed and currently is in widespread (global) use across GM. This paper describes GM's objectives and requirements for developing e-Thermal. The structure of the tool and the capabilities of the simulation tool modules (refrigeration, front end airflow, passenger compartment, engine, transmission, Interior air handling …) is introduced. Model data requirements and GM's strategy for acquiring component data are also described.

Vehicle requirements are measurable and define the performance of a system and its design constraints. Requirements are developed and translated from the voice of the buying customer, the voice of the government, and the voice of General Motors. Duramax powertrain subsystem requirements are developed from the vehicle requirements. This “flow down” approach optimizes the vehicle as a system. The packaging envelope, common interfaces, and manufacturing impacts were the outcome of the Vehicle Portfolio Development Process. Project execution was a global development process executed by Isuzu Engineers in Japan, Allison Automatic Transmission Engineers in Indianapolis, ZF Manual Transmission Engineers in Detroit, and General Motors Engineers in Detroit.

This paper presents a project that was done to solve an integration problem between a brake system and a cruise control system on a GM vehicle program, each of which was supplied by a different supplier. This paper presents how the problem was resolved using a CAE tool which was a combination of formulated MS/Excel spreadsheet, Overdrive (GM internal code), and iSIGHT of Engineous Software Inc, which is a process integrator and process automator. A sensitivity study of system reliability was conducted using iSIGHT. The most sensitive factor was found through the sensitivity study. Thereafter, a Robust design was obtained. The recommended Robust Design was implemented in the vehicle program, which led to a substantial cost saving. The CAE software tool (the combination) developed through the problem solving process will be used to ensure quality of brake and cruise system performance for future vehicle programs.

This paper presents a case study on reducing road noise of a passenger vehicle. SEA, insertion loss and sound intensity measurements were the tools used in the study. A SEA model was constructed to predict the primary paths (panels or area) contributing to the overall interior sound field. Insertion loss measurements were used to verify the primary contributing paths identified using SEA. To provide further details of the primary paths, intensity maps of identified panels were measured allowing detailed reconstruction of the contributory panels. The SEA model, insertion loss, and intensity maps aided in providing possible design fixes that will effectively reduce road noise. Finally, comparisons of predicted results versus actual results at both a subsystem and a full vehicle level are included in this paper.

In GM R&D Powertrain/Engine Control Group, rapid prototyping controller (RPC) systems with Matlab/Simulink are used extensively to design, simulate and implement advanced engine control algorithms and models. However, those RPC systems use powerful microprocessors with large amounts of RAM contrary to engine control modules (ECM) in production vehicles. Therefore, a thorough analysis on the comparatively much more complicated algorithms and models cannot be performed during the research stage, since there are not enough tools to enable the smooth transition from Matlab/Simulink to the production type processor. The Real-Time Interface (RTI) Blockset for a production like microprocessor would close the transition gap between rapid prototyping controller systems and production type microprocessors by leveraging the power and popularity of Matlab/Simulink in control engineering world and automatic code generation tools.

Different countermeasure designs for reducing the HIC (d) and to comply with FMVSS201U have been evaluated in many component-level studies by suppliers and OEMs. This study presents guidelines to support future countermeasure and interior designs. FMVSS201U has changed the way OEMs design interiors of the vehicles today. Most recently, much more work is being done to find ways to design interiors of the vehicles that comply with FMVSS201U while keeping the interiors aesthetically pleasing, attaining driver comfort and meeting driver visibility requirements. Introduction of side-rail airbags has further affected countermeasure design and packaging. This study focuses on several countermeasure designs in the side-rail region as used in a mid-sized vehicle implemented to meet FMVSS201U requirements and their efficiency with respect to Head Injury Criterion (HIC) reduction given a fixed packaging space.

General Motors Powertrain Division has developed the next generation big block V8 engine for introduction in the 1996 model year. In addition to meeting tighter emission and on-board diagnostic legislation, this engine evolved to meet both customer requirements and competitive challenges. Starting with the proven dependability of the time tested big block V8, goals were set to substantially increase the power, torque, fuel economy and overall pleaseability of GM's large load capacity gasoline engine. The need for this new engine to meet packaging requirements in many vehicle platforms, both truck and OEM, as well as a requirement for minimal additional heat rejection over the engine being replaced, placed additional constraints on the design.

In recent years a predominant strategy for setting sound quality (SQ) requirements has been the sensory correlation approach (also called sensory evaluation or sensory science). Some users of this approach have reported their progress in numerous papers. Other SQ practitioners have made presentations on specific topics that show the linkage to music and musical notation. These specific links point to an alternative general strategy - “the Music Analogy for Sound Quality.” This paper begins by comparing the general methods of the music analogy and sensory correlation. Some major differences will be identified and implications discussed. Some existing specific tools for the music analogy will be identified as well as some gaps that need to be filled. Finally, reasons will be presented concerning why the music analogy should be considered when developing sound quality requirements.

Two thread forming processes, rolling and cutting, were studied for their effects on fatigue in cast aluminum 319-T7. Material was excised from cylinder blocks and tested in rotating-bending fatigue in the form of unnotched and notched specimens. The notched specimens were prepared by either rolling or cutting to replicate threads in production-intent parts. Cut threads exhibited conventional notch behavior for notch sensitive materials. In contrast, plastic deformation induced by rolling created residual compressive stresses in the notch root and significantly improved fatigue strength to the point that most of the rolled specimens broke outside the notch. Fractographic and metallographic investigation showed that cracks at the root of rolled notches were deflected upon initiation. This lengthened their incubation period, which effectively increased fatigue resistance.

Any equipment system or vehicle component like the Convenience Organizer storage system needs to be retained within the cargo compartment without intruding into the passenger compartment for occupant safety during a high speed impact. This paper outlines a test method to evaluate the retention of such a system in a rear impact environment. The method utilizes a low speed barrier to simulate a high speed RMB (Rear Moving Barrier) impact. The content of the low speed RMB impact test setup was developed utilizing DYNA3D analytical simulation results from a full vehicle model subjected to high-speed RMB impact. The retention of the equipment developed through this test method was confirmed on a full scale rear impact test.

The past 10 years have created such buzzwords as “model-based development” and “auto-code generation”. Conveniently absent from the tool literature on model-based development are the equally, or more important concepts of Software Architecture and Process. When developing product line software, the process and architecture form a critical foundation to base reusable products and components. The development process can no longer be viewed as “model-based”, but rather as “model-driven”, due to the reliance on the models as the source artifact as opposed to the creators of the source artifacts. A model-driven product line software development process allows capturing of behavior, for commonality across different products, and having a different implementation for a specific product release.

General Motor's Corvette product engineering was given the challenge to find mass reduction opportunities on the painted body panels of the C6 Z06 through the utilization of carbon fiber reinforced composites (CFRC). The successful implementation of a carbon fiber hood on the 2004 C5 Commemorative Edition Z06 Corvette was the springboard for Corvette Team's appetite for a more extensive application of CFRC on the C6 Z06 model. Fenders were identified as the best application for the technology given their location on the front of the vehicle and the amount of mass saved. The C6 Z06 CFRC fenders provide 6kg reduction of vehicle mass as compared to the smaller RRIM fenders used on the Coupe and Convertible models.

Since its very beginning in 1953, Corvette has been a pioneer in light weight material applications. The new 6th generation corvette high performance Z06 model required aggressive weight savings to achieve its performance and fuel economy targets. In addition to aluminum body structure and some carbon fiber components, the decision to use a magnesium front crossmember was identified to help achieve the targets. An overview of the Structural Cast Magnesium Development (SCMD) project will be presented which will provide information on key project tasks. Project focus was to develop the science and technical expertise to manufacture and validate large structural magnesium castings, which provide a weight reduction potential of 35 percent with respect to aluminum. The die cast magnesium cradle is being produced from a Mg-Al-RE alloy, designated AE44, for high temperature creep and strength performance as well as casting ductility requirements.

Vehicle evaluations and model calculations were conducted on a vacuum-insulated catalytic converter (VICC). This converter uses vacuum and a eutectic PCM (phase-change material) to prolong the temperature cool-down time and hence, may keep the converter above catalyst light-off between starts. Tailpipe emissions from a 1992 Tier 0 5.2L van were evaluated after 3hr, 12hr, and 24hr soak periods. After a 12hr soak the HC emissions were reduced by about 55% over the baseline HC emissions; after a 24hr soak the device did not exhibit any benefit in light-off compared to a conventional converter. Cool-down characteristics of this VICC indicated that the catalyst mid-bed temperature was about 180°C after 24hrs. Model calculations of the temperature warm-up were conducted on a VICC converter. Different warm-up profiles within the converter were predicted depending on the initial temperature of the device.

Sound absorption is one way to control noise in automotive passenger compartments. Fibrous or porous materials absorb sound in a cavity by dissipating energy associated with a propagating sound wave. The objective of this study was to evaluate the acoustic performance of a cotton fiber absorbing material in comparison to a new polypropylene fibrous material, called ECOSORB ®. The acoustical evaluation was done using measurements of material properties along with sound pressure level from road testing of a fully-assembled vehicle. The new polypropylene fibrous material showed significant advantages over the cotton fiber materials in material properties testing and also in-vehicle measurements. In addition to the performance benefits, the polypropylene absorber provided weight savings over the cotton fiber material.

An onboard vehicle-to-vehicle multi-hop wireless networking system has been developed to test the real-world performance of telematics applications. The system targets emergency and safety messaging, traffic updates, audio/video streaming and commercial announcements. The test-bed includes a Differential GPS receiver, an IEEE 802.11a radio card modified to emulate the DSRC standard, a 1xRTT cellular-data connection, an onboard computer and audio-visual equipment. Vehicles exchange data directly or via intermediate vehicles using a multi-hop routing protocol. The focus of the test-bed is to (a) evaluate the feasibility of high-speed inter-vehicular networking, (b) characterize 5.8GHz signal propagation within a dynamic mobile ad hoc environment, and (c) develop routing protocols for highly mobile networks. The test-bed has been deployed across five vehicles and tested over 400 miles on the road.