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CAE Support to Vehicle Audio Installation Issues

Volvo Car Corporation-Andrzej Pietrzyk
  • Technical Paper
  • 2020-01-1575
To be published on 2020-06-03 by SAE International in United States
Audio CAE is an emerging area of interest for a vehicle OEM, despite the fact that the development of the audio system is often left to a specialized supplier. Especially the questions regarding early stages of the vehicle design, like choosing the possible positions for speakers, deciding the installation details that can influence the visual design, and integration of the low frequency speakers with the body & closures structure, are of interest. Therefore, at VCC, the development of the CAE methodology for audio applications has been undertaken. The long term goal is to enable performing subjective evaluation of sound in a virtual car, and integrating audio evaluation in the NVH simulator. The key to all CAE applications is the loudspeaker model made available in the vibro-acoustic software used within the company. Such a model has been developed, implemented and verified in different frequency ranges and different applications. The applications can be divided into the low frequency ones (concerning the installation of woofers and subwoofers), and the middle/high frequency ones (concerning the installation of midrange and…
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Finite Element Model Reduction Applied to Nonlinear Impact Simulation for Squeak and Rattle Prediction

Volvo Car Corporation-Mohsen Bayani Khaknejad, Casper Wickman
Chalmers University of Technology-Anoob Basheer, Filip Godborg, Rikard Söderberg
  • Technical Paper
  • 2020-01-1558
To be published on 2020-06-03 by SAE International in United States
Increasing demand for simulation accuracy often leads to increased model complexity, which in turn, results in higher computational costs. As a provision, Component Mode Synthesis approaches are employed to approximate the system response by using dynamic substructuring and model reduction techniques in linear systems. However, the use of available model reduction techniques in nonlinear problems has not been completely addressed. In this paper, the application of a Component Mode Synthesis method in squeak and rattle nonlinear simulation has been investigated. Critical regions for squeak and rattle of the side door model of a passenger car were modelled by nonlinear contact interfaces in finite element solution. Craig-Bampton model reduction method was employed to substructure the finite element model, while keeping the nonlinear contacts in the model. Model response was evaluated using Modal Assurance Criterion, frequency response analysis and contact force magnitude in comparison with the baseline model. Results showed that a great reduction in computational time (about 97%) can be achieved while the accuracy of the system response was maintained at an acceptable range for the…
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Experimental Evaluation of Novel Thermal Barrier Coatings in a Single Cylinder Light Duty Diesel Engine

Volvo Car Corporation-Joop Somhorst, Mirko Bovo
Chalmers Technical University-Michael Oevermann
  • Technical Paper
  • 2019-24-0062
Published 2019-09-09 by SAE International in United States
The objective of this investigation was to improve the thermal properties of plasma sprayed thermal barrier coatings (TBC) for internal combustion engines. There is a need for further reduction of thermal conductivity and volumetric heat capacity and the negative effects on heat loss and combustion phasing of surface roughness and permeable porosity, typical for plasma sprayed coatings, should be minimized. Four measures for improvement of TBC properties were evaluated: i) modification of the coating's microstructure by using a novel suspension plasma spraying method, ii) application of gadolinium-zirconate, a novel ceramic material with low thermal conductivity, iii) polishing of the coating to achieve low surface roughness, and iv) sealing of the porous coating surface with a polysilazane. Six coating variants with different combinations of the selected measures were applied on the piston crown and evaluated in a single cylinder light duty diesel engine. The experimental data was modeled with multiple linear regression to obtain confidence intervals for the measurement results and to correct the data for variations of surface roughness, combustion phasing and compression ratio for…
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Strive for Zero Emissions Impact from Hybrids

Volvo Car Corporation-Mats Laurell, Fredrik Ekström
Continental-Lorenzo Pace, Katrin Konieczny
Published 2019-09-09 by SAE International in United States
Since several decades, passenger cars and light duty vehicles (LDV) with spark-ignited engines reach full pollutant conversion during warm up conditions; the major challenge has been represented by the cold start and warming up strategies. The focus on technology developments of exhaust after treatment systems have been done in the thermal management in order to reach the warm up conditions as soon as possible. A new challenge is now represented by the Real Driving Emission (RDE) Regulation as this bring more various, and not any longer cycle defined, cold start conditions. On the other hand, once the full conversion has been reached, it would be beneficial for many Exhaust After Treatment System (EATS) components, e.g. for overall durability if the exhaust gas temperature could be lowered. To take significant further emission steps, approaching e.g. zero emission concepts, we investigate the use of Electrical Heating Catalyst (EHC) also including pre-heating.The clear goal is to have the right temperature in the right place at the right time. Several approaches have been investigated in this paper regarding EATS…
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A Mild Hybrid SIDI Turbo Passenger Car Engine with Organic Rankine Cycle Waste Heat Recovery

Volvo Car Corporation-Fredrik B. Ekström, Ola Rolandson, Soren Eriksson, Christer Odenmarck, Mattias Svensson, Andreas Eriksson, Hans Olsen
Published 2019-09-09 by SAE International in United States
While striving for more fuel-efficient vehicles, all possible measures are considered to increase the efficiency of the combustion engine powertrain. 48V mild hybrid technology is one such measure, SIDI (Spark Ignited Direct Injection) engines with Miller technology are another, while recovering energy from the engine’s waste heat (WHR) is yet another option.In this paper, results will be published from an advanced engineering project at Volvo Cars including all of these components. An ethanol based Organic Rankine Cycle (ORC) WHR-system was successfully built around a 4-cylinder, 2.0 litre SIDI-engine, including 48V mild hybrid technology, with vehicle packaging considered. A dedicated control system was also developed for the ORC system including communication between it and the engine. The ORC system uses the engine exhaust as the heat source, for which a purpose-built evaporator was designed and built to fit in the vehicle tunnel. The expansion of the ethanol vapour occurs in an axial piston expander coupled both electrically to the hybrid system and mechanically to the engine crankshaft via a belt-drive. This dual power output from the…
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Interaction between Fuel Jets and Prevailing Combustion During Closely-Coupled Injections in an Optical LD Diesel Engine

Volvo Car Corporation-Michael Denny, Håkan Persson
Lund University-Alexios Matamis, Mattias Richter, Öivind Andersson
Published 2019-04-02 by SAE International in United States
Two imaging techniques are used to investigate the interaction between developed combustion from earlier injections and partially oxidized fuel (POF) of a subsequent injection. The latter is visualized by using planar laser induced fluorescence (PLIF) of formaldehyde and poly-cyclic aromatic hydrocarbons. High speed imaging captures the natural luminescence (NL) of the prevailing combustion. Three different fuel injection strategies are studied. One strategy consists of two pilot injections, with modest separations after each, followed by single main and post injections. Both of the other two strategies have three pilots followed by single main and post injections. The separations after the second and third pilots are several times shorter than in the reference case (making them closely-coupled). The closely-coupled cases have more linear heat release rates (HRR) which lead to much lower combustion noise levels. For all cases, POF is detected during the very weak HRR before the notable combustion of the first pilot injection’s fuel. When the subsequent fuel injections overlap with a local decrease in HRR, the prevailing combustion is to some degree extinguished during…
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Uncertainty Quantification of Flow Uniformity Measurements in a Slotted Wall Wind Tunnel

Volvo Car Corporation-Alexander Broniewicz
Chalmers University of Technology-Emil Ljungskog, Simone Sebben
Published 2019-04-02 by SAE International in United States
The need for a more complete understanding of the flow behavior in aerodynamic wind tunnels has increased as they have become vital tools not only for vehicle development, but also for vehicle certification. One important aspect of the behavior is the empty test section flow, which in a conventional tunnel should be as uniform as possible. In order to assess the uniformity and ensure consistent behavior over time, accurate measurements need to be performed regularly. Furthermore, the uncertainties and errors of the measurements need to be minimized in order to resolve small non-uniformities. In this work, the quantification of the measurement uncertainties from the full measurement chain of the new flow uniformity measurement rig for the Volvo Cars aerodynamic wind tunnel is presented. The simulation based method used to account for flow interference of the probe mount is also discussed. The flow measurement rig is custom made to facilitate fast and accurate measurements with low interference. The cost is minimized by using standard off-the-shelf five hole probes and facility installed pressure measurement instrumentation, which are…
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The Effects of Wheel Design on the Aerodynamic Drag of Passenger Vehicles

SAE International Journal of Advances and Current Practices in Mobility

Volvo Car Corporation-Henrik Berg, Linda Josefsson
Chalmers University of Technology-Adam Brandt, Michael Bolzon
  • Journal Article
  • 2019-01-0662
Published 2019-04-02 by SAE International in United States
Approximately 25 % of a passenger vehicle’s aerodynamic drag comes directly or indirectly from its wheels, indicating that the rim geometry is highly relevant for increasing the vehicle’s overall energy efficiency. An extensive experimental study is presented where a parametric model of the rim design was developed, and statistical methods were employed to isolate the aerodynamic effects of certain geometric rim parameters. In addition to wind tunnel force measurements, this study employed the flowfield measurement techniques of wake surveys, wheelhouse pressure measurements, and base pressure measurements to investigate and explain the most important parameters’ effects on the flowfield. In addition, a numerical model of the vehicle with various rim geometries was developed and used to further elucidate the effects of certain geometric parameters on the flow field. The results showed that the most important parameter was the coverage area, and it was found to have a linear effect on the aerodynamic drag. Interestingly, parameters associated with the outer radial region of wheel (rim cover) were also found to be significant, along with the wheel depth…
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Accuracy and Speed for Scale-Resolving Simulations of the DrivAer Reference Model

Volvo Car Corporation-Torbjörn Virdung
Creo Dynamics-Torbjörn Larsson
Published 2019-04-02 by SAE International in United States
In aerodynamic development of ground vehicles, the use of Computational Fluid Dynamics (CFD) is crucial for improving the aerodynamic performance, stability and comfort of the vehicle. Simulation time and accuracy are two key factors of a well working CFD procedure. Using scale-resolving simulations, accurate predictions of the flow field and aerodynamic forces are possible, but often leads to long simulation time. For a given solver, one of the most significant aspects of the simulation time/cost is the temporal resolution. In this study, this aspect is investigated using the realistic vehicle model DrivAer with the notchback geometry as the test case. To ensure a direct and accurate comparison with wind tunnel measurements, performed at TU Berlin, a large section of the wind tunnel is included in the simulation domain. All simulations are performed at a Reynolds number of 3.12 million, based on the vehicle length. Three spatial resolutions were compared, where it could be seen that a hybrid element mesh consisting of 102 million cells only revealed small differences to the finest mesh investigated, well as…
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Feature-Based Response Classification in Nonlinear Structural Design Simulations

SAE International Journal of Vehicle Dynamics, Stability, and NVH

Volvo Car Corporation-Niclas Andersson, Raoul Rinaldo
Chalmers University of Technology-Thomas Abrahamsson
  • Journal Article
  • 10-02-03-0012
Published 2018-07-24 by SAE International in United States
An applied system design analysis approach for automated processing and classification of simulated structural responses is presented. Deterministic and nonlinear dynamics are studied under ideal loading and low noise conditions to determine fundamental system properties, how they vary and possibly interact. Using powerful computer resources, large amounts of simulated raw data can be produced in a short period of time. Efficient tools for data processing and interpretation are then needed, but existing ones often require much manual preparation and direct human judgement. Thus, there is a need to develop techniques that help to treat more virtual prototype variants and efficiently extract useful information from them. For this, time signals are evaluated by methods commonly used within structural dynamics and statistical learning. A multi-level multi-frequency stimulus function is constructed and simulated response signals are combined into frequency domain functions. These are associated with qualitative system features, such as being periodic or aperiodic, linear or nonlinear and further into subcategories of nonlinear systems, such as fundamental, sub or super harmonic and even or odd order types. Appropriate…
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