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The feasibility of a recently developed eddy-resolving model of turbulence, termed as Very LES (Large-Eddy-Simulation), was tested by simulating the flow dynamics in two moving piston-cylinder assemblies. The first configuration deals with the compression of a tumbling vortex generated during the intake process within a cylinder with the square cross-sectional area, for which the reference experimental database was made available by Borée et al. (2002). The second piston-cylinder assembly represents a realistic motored IC-Engine (Internal-Combustion Engine) with the multiple Y-shaped intake and outtake ducts in which the movable valves are accommodated. The boundary and operating conditions correspond to the experimental study performed by Baum et al. (2014). The VLES simulation model applied presently is a seamless eddy-resolving hybrid RANS/LES (Reynolds-Averaged Navier-Stokes / Large-eddy Simulation) model.

This paper outlines an improved computational methodology to simulate the immersion quenching heat transfer characteristics. Main applicability of the presented method lays in virtual experimental investigation of the heat treatment of cast aluminum parts, above all cylinder heads of internal combustion engines. The boiling phase change process between the heated part and a sub-cooled liquid domain is handled by using the Eulerian multi-fluid modeling approach, which is implemented within the commercial Computational Fluid Dynamics (CFD) code AVL FIRE®. Solid and liquid domains are treated simultaneously. While for the fluid domain mass, momentum and energy equations are solved in the context of multi-fluid modeling approach, only the energy equation is solved to predict the thermal field in the solid region. For the presented quenching simulation, the solid and fluid parts are contained in a single domain.

Increasing demands on the capabilities of engine simulation and the ability to accurately predict both performance and acoustics has lead to the development of multiple approaches, ranging from fully 3D to simplified 1D models. In this work it will be described the development and application of hybrid 1D-3D approaches and an innovative one based on the 3D cell element. This is designed to model the acoustics of intake and exhaust system components used in internal combustion engines. Models of components are built using a network or grid of 3D cells based primarily on the geometry of the system. This means that these models can be built without fundamental knowledge of acoustically equivalent systems making their range of application larger as well as making them simpler to construct. Due to the 3D nature of these models it is also possible to predict higher order modes and improve the accuracy of models at high frequencies compared to conventional plane wave approaches.

The aim of this work has been to investigate the influence of bio-diesel (FAME - fatty acid methyl ester) and reasonable blends of FAME and diesel, on the behavior of the mixture formation, the combustion process and the emission levels of a modern diesel engine. Therefore experimental investigations have been carried out on a single cylinder engine which is a modification of a four cylinder production HSDI (high speed direct injection) diesel engine. Cylinder pressure and tail-pipe emissions have been measured. Additionally the injector has been mounted on a flow-metering device to gather information about the pure flow through the injection system depending on the fuel type. In parallel with the experimental investigations CFD (computational fluid dynamics) calculations have been carried out in order to closely check local effects inside the injector and the combustion chamber.

In a fast and cost-efficient powertrain development process several optimization and validation tasks are required at early development stages, where prototype vehicles are not available. Especially for hybrid powertrain concepts the development targets for fuel consumption, vehicle performance, functional safety and durability have to be validated on the engine test bed before integration and testing with real vehicle prototypes takes place. The integration of relevant control unit functions like transmission shift or vehicle stability as AUTOSAR software component into a simulation system at the engine test bed allows a fast and integrated workflow for series development. Complementary a high-quality combustion torque estimation and the consideration of driver behavior and lateral vehicle dynamics improve the correlation of simulated to real world driving maneuvers.

The paper is devoted to the theoretical and experimental analysis of the piezoelectric injector of a modern common rail system. A detailed one-dimensional dynamic model of the injector is created using AVL software Hydsim. It consists of multiple hydraulic and mechanical components for the modeling of the compressible fuel flow and dynamic motion of the solid parts including elastic deformation. Furthermore, the injector model contains the electro-mechanical description of the piezoelectric stack actuator with the hysteresis behavior. Specific aspects of the piezo-actuator modeling are discussed. Different operating conditions of the injection system are modeled and tested. These conditions are defined for a specific diesel engine and include full and part load cases with multiple pilot and main injections. Two fuel types are chosen for the investigation: conventional diesel and FT-kerosene based on Fischer-Tropsch synthesis. The performance of the injection system is discussed.

Hybrid vehicles are characterized by a combination of mechanical, electrical and control components. The complexity of this mechatronic system requires new methods and tools for a successful development of new hybrid vehicle concepts. It is now possible to accomplish certain tasks earlier in the development projects using virtual prototypes of the powertrain components and the vehicle. The process called “frontloading” integrates simulation, optimization and validation in earlier development phases of a vehicle and prevents from having cost intense problems in later development phases. Besides the reduction of emissions and fuel consumption also the subjective impression of the vehicle driveability are main goals for the optimization of hybrid powertrains.

Several models have been developed for specific applications to accurately represent the dynamics of IC engines with particular focus on NVH behavior. These models aim to investigate the speed irregularity of crankshaft, the vibration level of the engine block and the engine mount vibrations. The speed fluctuations of the crankshaft causes timing drive excitations and the well known gear rattle phenomena. Engine block vibrations can be used as a reference for the radiated noise. Lastly, engine mount vibrations directly contribute to the cabin noise. With the reduction of engine noise, the gearbox noise becomes more audible. Therefore, it is necessary to extend the MBD (Multi Body Dynamic) model, used for vibration and acoustic analysis of the power unit, in the gearbox direction. In this paper a model is presented, which was developed in joint collaboration between Elasis S.C.p.A. and AVL List GmbH.

One of the ways to represent the crankshaft in a 3D engine dynamic simulation is by using structured model consisting of nodes and binary elastic elements. The paper presents a methodology for automatic generation of this kind of models, starting from CAD data. The main advantage of the method - implemented as a software tool - is a significant reduction in time to model the crankshafts, and hence the overall project time. The calculation results show a good correlation with those obtained by commonly used FEA software.

The paper presents the-state-of-the-art numerical simulation of the flow around vehicles by examining a number of various industrial benchmarks. A selection of results, obtained by a finite volume numerical code based on the Reynolds-Averaged Navier Stokes (RANS) approach, illustrates the capability of Computational Fluid Dynamics (CFD) to provide accurate and reliable solutions in the area of external car aerodynamics. Benchmarks presented here are Peugeot 405 model, SAE Notchback Reference Body and VW-CFD model. Due attention was given to the reduction of both numerical as well as turbulence modeling error. This also includes the use of second-order accurate differencing schemes for convection terms and the full Reynolds-stress model to model Reynolds stresses. The computations showed a substantial difference in the flow patterns predicted by the standard k-ε model and by the full Reynolds-stress model.