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Rauch C.,Virtual Vehicle Research and Test Center ViF | Almbauer R.,University of Graz | Almbauer R.,Institute for Internal Combustion Engines and Thermodynamics
10th AIAA/ASME Joint Thermophysics and Heat Transfer Conference | Year: 2010

This paper is devoted to uncertainties stemming from view factors. The equations for local sensitivity and uncertainty analysis are derived for diffuse-gray thermal radiation cases coupled with conduction and convection. A numerical analysis of the resulting equations is conducted. A simple test case is used to demonstrate the influence of the heat transfer modes on view factor uncertainties. © 2010 by the American Institute of Aeronautics and Astronautics, Inc. Source


Meierhofer A.,Virtual Vehicle Research and Test Center ViF | Hardwick C.,University of Sheffield | Lewis R.,University of Sheffield | Six K.,Graz University of Technology | Dietmaier P.,Graz University of Technology
9th International Conference on Contact Mechanics and Wear of Rail/Wheel Systems, CM 2012 | Year: 2012

When adding substances to the wheel-rail contact, they mix with wear particles and form a Third Body Layer (3BL). This layer influences the initial gradient of the traction characteristic. During twin-disc tests presented in this article, a granular layer consisting of iron, haematite, and magnetite with a thickness of 20 μm to 60 μm was found. In addition, a new contact model is presented that uses non-linear properties of the 3BL to describe its influence on the traction characteristic. The results of the model were compared to the results of the experiment. A qualitative and quantitative agreement was achieved. This will improve, e.g., the quality of vehicle dynamics simulations, optimisations of control devices for traction and breaking, and predictions of wear and damage on wheel and rail. Source


Krammer M.,Virtual Vehicle Research and Test Center ViF | Armengaud E.,Virtual Vehicle Research and Test Center ViF | Bourrouilh Q.,AVL List GmbH
Proceedings - 37th EUROMICRO Conference on Software Engineering and Advanced Applications, SEAA 2011 | Year: 2011

The introduction of the new automotive standard on functional safety ISO 26262 raises different challenges from the process point of view. Hence, a standardized process mapping roles, activities and work products according to ISO 26262 needs to be defined. This process has to be tailored according to the automotive safety integrity level (ASIL) and to company specific practices and teams. In this work, we propose a method content approach modeled with SPEM in order to define and formalize development processes, enabling better management and easier tailoring activities. © 2011 IEEE. Source


Wang X.,Virtual Vehicle Research and Test Center ViF | Steiner A.,Virtual Vehicle Research and Test Center ViF | Fiala J.,Virtual Vehicle Research and Test Center ViF
Applied Mechanics and Materials | Year: 2012

This article presents the approach of quasi LPV (Linear Parameter-Varying) modeling techniques for an air conditioning system of an electric vehicle. Vehicle air conditioning systems are strongly non-linear systems and it is a challenging task to get a precise real time model for control purposes. Therefore, an LPV method is first introduced to estimate the air conditioning system. Experimental results show that the LPV model delivers a very high accuracy for the COP (Coefficient Of Performance) estimation, that can't be reached by traditional identification methods. Some discussion about the model structure and its application are presented and a non-linear LPV model structure similar to the Hammerstein structure is proposed. © (2012) Trans Tech Publications, Switzerland. Source

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