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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.

In order to enable the regeneration of NOx traps at low temperatures and reduce the fuel penalty, an innovative fuel reformer has been developed to create a hydrogen-rich gas from diesel fuel to be used as the NOx reductant. This paper outlines the experimental use of this hydrogen generation device on a dual-leg NOx trap system with an 8.3L diesel engine. The system was tested at six ESC modes, and gave satisfactory results at those engine conditions where the NOx trap had good adsorption capacity (exhaust temperature < 450 °C). With the NOx conversion efficiency of 80% as the target, the fuel economy penalty was about 3% for most engine conditions. Since this type of diesel engines are widely used for urban transit buses, the system was also tested at six typical road conditions and showed satisfactory results in terms of both NOx conversion efficiency and fuel economy penalty. A comparison with diesel fuel as the NOx reductant was conducted with the same test setup.

Catalytic converters are typically constrained and cushioned by an intumescent mat material that is critical to the durability of the ceramic and metallic substrates. In an effort to reduce costs and improve designs, this work attempts to develop and verify a material model for the mat that can be utilized in predictive analysis. Test data are used in conjunction with the finite element program ABAQUS™ to create both a hyperfoam and a user-defined material model. These models will be verified and compared by modelling with ABAQUS the specimens and test conditions used to generate the data.

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.