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At the initial accessory drive system design stage, a model was created using commercial CAE software to predict the dynamic response of the pulleys, tensioner motion and pulley slip. In a typical 6 cylinder automotive accessory drive systems, the first system torsional mode is near the engine idle speed. The combination of these two events could generate numerous undesirable noise and vibration effects in the system. Data acquisition on a firing engine with a powertrain dynamometer confirmed the computer model's results. Correlations are then developed and established based on results between the firing engine to the CAE model to increase confidence in the generated model. Further system optimization through design modifications are used to tune the system to minimize the overall system dynamics.

The Controller Area Network (CAN) provides the user with several parameters to configure the bit timing, sampling point, and bit rate. With this flexibility comes some complexity in choosing the correct values for these parameters and properly configuring the bit rate. A given bit rate can be achieved by setting these parameter in more than one way. It is also possible to incorrectly configure these parameters and achieve a close enough bit rate that will allow the system to function but not perform in an optimized manner. This paper discusses how to calculate the bit rate and how to choose some of these parameters. A set of equations were developed and used in an example to configure the bit rate for a PIC18FXX8 CAN controller.

In this paper, loads acting on driveline components during an entire proving ground (PG) durability schedule are used to demonstrate the methodology of optimizing driveline performance reliability using both physical and computational methods. It is well known that there is an effect of driver variability on the driveline component loads. Yet, this effect has not been quantified in the past for lack of experimental data from multiple drivers and reliable data analysis methods. This paper presents the data reduction techniques that are used to identify the extreme driver performance and to extrapolate the short-term measurement to long-term data for driveline performance reliability. The driveline loading variability is made evident in the rotating moment histogram domain. This paper also introduces the concept for a simulation model to predict the driveline component loads based on a complete proving grounds schedule. A model-to-test correlation is also performed in this paper.

Improving catalyst light-off characteristics during cold start and reducing engine-out (more accurately converter-in) emissions prior to catalyst light-off have been regarded as the keys to meeting future stringent emissions regulations. Many technologies and control strategies have been proposed, and some of them have already been incorporated into production, to address these issues. Among these, secondary air injection received a lot of attention. This study was initiated to investigate the thermal and chemical processes associated with secondary air injection inside the exhaust system in order to maximize the simultaneous benefit of improving catalyst light-off performance and reducing converter-in emissions. The effects of several design and operating parameters such as secondary air injection location, exhaust manifold design, spark timing, engine enrichment level, and secondary air flow rate were carefully examined.

Sheet metal stamping involves a system of complex tribological (friction, lubrication, and wear), heat transfer, and material strain interactions. Accurate coefficient of friction, strain, and lubrication regime data is required to allow proper modeling of the various sheet stamping processes. In addition, non-intrusive means of monitoring the coefficient of friction in production stamping operations would be of assistance for efficiently maintaining proper stamping quality and to indicate when adjustments to the various stamping parameters, including maintenance, would be advantageous. One of the key sub-systems of the sheet metal stamping process is the draw bead. This paper presents an investigation of the tribology of the draw bead using a Draw Bead Simulator (DBS) Machine and automotive zinc-coated sheet steels. The investigation and findings include: 1) A new, non-intrusive method of measuring the surface temperature of the sheet steel as it passes through the draw bead.

Traditionally, high-strength low-alloy (HSLA) steel is used for automotive vehicle weight reduction in the North American automotive industry. Dual phase (DP) high strength steel has gained great attention because it provides a combination of high strength and good formability. The main advantage of DP steel is the high ratio of tensile strength to yield strength, which provides more flexibility in stamping and higher energy absorption in a component crush event. This study compares the performances of DP and HSLA steel grades in stamping processes and component crush events, as shown in a typical automotive unibody inner rail. Simulation results show that DP steel offers more uniform strain distribution, improved formability, and better crush performance than conventional HSLA steel.

The effect of forming strains on the fatigue behavior of an automotive mild steel, interstitial free steel, was studied after being prestrained by balanced biaxial stretch and plane strain. In the long life region, higher than 5×105 reversals, prestrain improves fatigue resistance. In the short life region, prestrain reduces fatigue resistance. At even shorter fatigue lives, the detrimental effect of prestrain diminishes. For plane strains, the fatigue behavior is anisotropic. In the direction perpendicular to the major strain, the steel exhibits much better fatigue resistance than in the direction parallel to the major strain.

The springback behavior might be different due to different gap clearances between die and punch. A study using FEA simulation is done to investigate the die gap effect. A 3D brick element and an explicit-implicit method are employed to investigate a few simple problems. A draw form, a crash form with an upper pad and a flange form are investigated separately. Numisheet’93 2D draw bending springback problem is also investigated using an explicit dynamic code. Comparisons between springback simulation results on several different die gaps are illustrated. The Kirchhoff assumption of C° shell element and the Mindlin/Love assumption of thin shell element are also examined on different cases. A case study then is performed on a rail type panel. Conclusions and recommendations for future studies are summarized.

This paper will provide an overview of the need, requirements, and constraints governing the development and application of polymer composites in automotive body components. It will discuss the efforts underway to lead and support the technology developments required for the cost-effective application of these new materials in mass-produced vehicles. The requirements and constraints of customer-driven, mass-produced, energy-efficient vehicles with uncompromised cost, capacity and performance, drive careful consideration of an injection-molded thermoplastic approach to a composite automotive body. Recent progress with this approach will be reported and some next steps examined.

An assessment of stamped part quality and launch readiness occurs at many intervals. This paper will focus on dimensional control activities that take place after Stamping Dies are constructed, but prior to producing the stamped parts. Die certification and die repeatability measurements have been performed at DaimlerChrysler and the results are documented. This die certification process provides an opportunity to uncover and resolve die machining issues with respect to the part math model or pre-engineered compensation model prior to producing parts. Additionally, the die repeatability process is performed to determine the ability of the die gaging to locate the incoming in-process material consistently. This paper will explain the die certification and die repeatability processes and share what we have learned. It will describe the processes, the tools, the participants, the sites, the benefits, and the measurement equipment.