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One of the key premises of the ISO 26262 functional safety standard is the development of an appropriate Technical Safety Concept for the item under development. This is specified in detail in Part 4 of the standard - Product development at the system level. The Technical safety requirements and the technical safety concept form the basis for deriving the hardware and software safety requirements that are then used by engineering teams for developing a safe product. Just like any other form of product development, making multiple revisions of the requirements are highly undesirable. This is primarily due to cost increases, chances of having inconsistencies within work products and its impact on the overall project schedule. Good technical safety requirements are in fact the foundation for an effective functional safety implementation.

In ISO 26262, the top-level safety goals are derived using the Hazard Analysis and Risk Assessment. Functional safety requirements (FSRs) are then derived from these safety goals in the concept phase (ISO 26262-3:2011). The standard does not call out a specific method to develop these FSRs from safety goals. However, ISO 26262-8:2011, Clause 6, does establish requirements to ensure consistent management and correct specification of safety requirements with respect to their attributes and characteristics throughout the safety lifecycle. Hence, there are expectations on the part of system engineers to bridge this gap. The method proposed in this paper utilizes concepts from process modeling to ensure the completeness of these requirements, eliminate any external inconsistencies between them and improve verifiability.

The complexity of both hardware and software has increased significantly in automotive over the past decade. This is apparent even in the compact passenger car market segment where the presence of electronic control units (ECU) has nearly tripled. In today's luxury vehicles, software can reach 100 million lines of code and are only projected to increase. Without preventive measures, the risk of safety-related system malfunction becomes unacceptably too high. The functional safety standard ISO 26262, released as first edition in 2011, provides crucial safety-related requirements for passenger vehicles. Although the standard defines the proper development for safety-related systems to ensure the avoidance of a hazard, it's implication for electromagnetic compatibility (EMC) is not clearly defined. This paper outlines the impact of ISO 26262 for EMC related issues, and discusses the standard's implications for EMC requirements on the present EMC practices for production vehicles.

Due to increasing concerns with petroleum usage and the increasing federal fuel economy regulations, electric powertrains have become more accepted by automotive manufacturers. The lithium-ion batteries employed in such systems are typically managed by an electronic battery management system (BMS). The BMS manages the battery to prevent thermal runaway and related thermal events, and is responsible for safety related functions such as thermal management, cell balancing, and controlling the connection to the vehicle's high-voltage DC bus. The ISO 26262 standard, introduced in final form in 2011, provides a framework for developing and validating automotive products that are safe from electronic and electrical system malfunctions, including BMS malfunctions, in passenger vehicles. This paper discusses options for BMS system development in accordance with ISO 26262. Hazards and risks of BMS malfunctions are identified and classified according to the standard.

An aftertreatment system for medium and heavy-duty diesel engines has been modeled for U.S. 2010 application. The aftertreatment system is comprised of a lean NOx trap (LNT) and an ammonia selective catalytic reduction (SCR) catalyst in series. Descriptions of the fully transient, one-dimensional LNT and SCR models are presented. The models simulate flow, heat transfer, and chemical reactions in the LNT and SCR catalysts. The models can be used to predict catalyst performance over a range of operating conditions and driving cycles. Simulated results of NOx conversion efficiency, species concentrations, and gas temperature were compared to experimental data for a 13-mode test. The model results showed the LNT-SCR model predicts system performance with reasonable accuracy in comparison to experimental data. Therefore, two model applications were investigated. First, LNT and SCR volumes were varied to examine the effect on NOx conversion efficiency and NH3 production.

Non-linear FEA models are applied to three different catalytic converters, with the objective of predicting structural parameters such as shell deformation, push-out force, and mounting-system contact pressure under various conditions. The FEA modeling technique uses a novel constitutive model of the intumescent mat material typically found in ceramic-monolith converter designs. The mat constitutive model accounts for reversible and irreversible thermal expansion, allowing for the prediction of the one-way converter deflection observed in hot durability tests. In addition to this mat material model, the FEA methodology accounts for elastic and plastic shell deformation, contact between materials, and a three-dimensional temperature field in the shell and mat. For each of three designs, predictions are presented for converter canning, heat-up, and cool-down (i.e., post-heating) conditions.

A comprehensive CFD-based modeling approach is applied to several automotive catalytic converters, with the objective of predicting thermal behavior under steady-state, high-load conditions. Specialized computational models are used to account for effects of heat and mass transfer in the monolith, oxidation reactions, heat generation, conjugate heat transfer in the various converter materials, and radiation heat transfer. These various physical considerations are assembled in a comprehensive CFD model, which is solved using state-of-the-art computational techniques. Detailed temperature measurements, taken in engine-cell experiments at Ohio State University's Center for Automotive Research, are used to validate the CFD models. Excellent agreement seen between measured and computed temperatures, both inside the converter assembly and on the outer shell.

Computational fluid dynamics methods are applied to the intake regions of a diesel engine in the design stage at Caterpillar. Using a complete, tested and validated computational methodology, fully viscous 3-D turbulent flow simulations are performed for three valve lifts, with the goal of identifying and understanding the physics underlying loss in the intake regions of IC engines. The results of these simulations lead to several design improvements in the intake region. These improvements are made to the computational domain, and flow simulations are again performed at three different valve lifts. Improvements in overall total pressure loss of between 5% and 33% are found in the computed results between the original and modified (improved) domains. Physical mechanisms responsible for these improvements are documented in detail.

A computational methodology has been developed for loss prediction in intake regions of internal combustion engines. The methodology consists of a hierarchy of four major tasks: (1) proper computational modeling of flow physics; (2) exact geometry and high quality and generation; (3) discretization schemes for low numerical viscosity; and (4) higher order turbulence modeling. Only when these four tasks are dealt with properly will a computational simulation yield consistently accurate results. This methodology, which is has been successfully tested and validated against benchmark quality data for a wide variety of complex 2-D and 3-D laminar and turbulent flow situations, is applied here to a loss prediction problem from industry. Total pressure losses in the intake region (inlet duct, manifold, plenum, ports, valves, and cylinder) of a Caterpillar diesel engine are predicted computationally and compared to experimental data.

On May 3, 1985, Republic Airlines (now Northwest Airlines) dry stripped with plastic media blast (PMB) their first DC-9 aircraft in Atlanta, Georgia. Four days later, Hill Air Force Base began production in their new facility designed to dry strip F-4 fighter aircraft in Ogden, Utah. These two important steps initiated the first generation of airline and military production PMB dry stripping. After this inception of the PMB process, numberable questions were raised pertaining to structural safety after being subjected to dry stripping. In the intervening four years, process improvements have been made and test data accumulated to verify safety of the PMB process. Boeing, with approval by the Federal Aviation Administration (FAA), has issued their specification for plastic media (PMB) dry stripping of airframes, Document D6-54705, PLASTIC MEDIA ABRASIVE STRIPPING OF ORGANIC FINISHES. We consider this to be the start of the second generation airliner dry stripping program.