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Technical Paper

Free Multibody Cosimulation Based Prototyping of Motorcycle Rider Assistance Systems

2020-10-30
2020-32-2306
Due to the increasing computational power, significant progress has been made over the past decades when it comes to CAD, multibody and simulation software. The application of this software allows to develop products from scratch, or to investigate the static and dynamic behavior of multibody models with remarkable precision. In order to keep the development costs low for highly sophisticated products, more precisely motorcycle rider assistance systems, it is necessary to focus extensively on the virtual prototyping using different software tools. In general, the interconnection of different tools is rather difficult, especially when considering the coupling of a detailed multibody model with a simulation software like MATLAB Simulink. The aim of this paper is to demonstrate the performance of a motorcycle rider assistance algorithm using a cosimulation approach between the free multibody software called FreeDyn and Simulink based on a sophisticated multibody motorcycle model.
Technical Paper

Novel Modelling Techniques of the Evolution of the Brake Friction in Disc Brakes for Automotive Applications

2020-10-05
2020-01-1621
The aim of the presented research is to propose and benchmark two brake models, namely the novel dynamic ILVO model and a neural network based regression. These can estimate the evolution of the brake friction between pad and disc under different load conditions, which are typically experienced in vehicle applications. The research also aims improving the knowledge of the underlying mechanism related to the evolution of the BLFC (boundary layer friction coefficient), the reliability of virtual environment simulations to speed up the product development time and reducing the amount of vehicle test in later phases and finally improving brake control functions. With the support of extensive brake dynamometer testing, the proposed models are benchmarked against State-of-the-Art. Both approaches are parametrised to render the friction coefficient dynamics with respect to the same input parameters.
Technical Paper

Development of Friction Materials Regulations for Four Latin American Countries

2020-10-05
2020-01-1615
Brakes are the most important safety device in a vehicle, however there are few barriers to manufacture, import, or sell friction materials in most of the countries, including USA. European countries, with the ECE R90 program, are a big exception. International Transport Forum published in 2016 the “Benchmarking of road safety in Latin America” report, it mentions that worldwide 17.5 people in every 100,000 die in road accidents, however Andean countries mortality rate is 23.4 and South American 21.0, considerably higher than the worldwide average.
Technical Paper

Comparison of Particulate Matter and Number Emissions from a Floating and a Fixed Caliper Brake System of the Same Lining Formulation

2020-10-05
2020-01-1633
The particulate emissions of two brake systems where characterized in a dilution tunnel optimized for PM10 measurements. The larger of them employed a fixed caliper (FXC) and the smaller one a floating caliper (FLC). Both used ECE brake pads of the same lining formulation. Measured properties included gravimetric PM2.5 and PM10, Particle Number (PN) concentrations of both untreated and thermally treated (according to exhaust number regulation) particles using Condensation Particle Counters (CPCs) having 23 and 10 nm cut-off sizes, and an Optical Particle Sizer (OPS). The brakes were tested over a novel test cycle developed from the database of the Worldwide harmonized Light-Duty vehicles Test Procedure (WLTP). A series of WLTP tests were performed starting from unconditioned pads, to characterize the evolution of emissions until their stabilization. Selected tests were also performed over a short version of the Los Angeles City Cycle.
Technical Paper

Potentials and Challenges of a Brake Particle Emission Collecting System

2020-10-05
2020-01-1635
Brake particle emissions as a part of non-exhaust emissions are becoming more and more relevant, various international research activities can be stated. Also from the legislation side, first hints are given in regards of possible regulations. One possible approach for the reduction of brake particle emissions deals with the collection of those particles close to the foundation brake. The presented paper will follow such an approach and give some insights. In a first step, the technical layout is described for bench and vehicle testing. While for bench testing a PMP-like style of the setup could be chosen, the vehicle test setup is oriented on conventional wheel dust measurements. Hence, presented results of laboratory testing are dealing with PN and PM measurements. Also the impact on particle size distribution is discussed. It can be stated, that the particle collecting system is able to improve PN and PM emissions. Additionally, ultra-fine particles are almost eliminated.
Technical Paper

A Hybrid Approach for the Assessment of Paths in Pass-by Maneuver

2020-09-30
2020-01-1550
Current vehicle regulations demand for a challenging decrease in the overall exterior noise as a benefit for the health of citizens and road users. New limits have been implemented in UN R51.03 (based on ISO 362-1:2015) to reduce the emitted noise both at constant speed and in full load so as to cover most of the real urban driving conditions. In order to achieve those targets the carmakers have to refine the trim of their vehicle and an experimental approach can take place too late. This paper shows a method for the pass by noise simulation exploiting the numerical transfer functions and a library of experimentally characterized sources with the aim to reduce the noise and find out a better tradeoff between costs and effectiveness of the modifications. Moreover a simple software tool for the treatment of the data and to ease the workflow has been created and used for the rank assessment of the different paths.
Technical Paper

A Priori Analysis of Acoustic Source Terms from Large-Eddy Simulation in Turbulent Pipe Flow

2020-09-30
2020-01-1518
The absence of combustion engine noise pushes increasingly attention to the sound generation from other, even much weaker, sources in the acoustic design of electric vehicles. The present work focusses on the numerical computation of flow induced noise, typically emerging in components of flow guiding devices in electro-mobile applications. The method of Large-Eddy Simulation (LES) represents a powerful technique for capturing most part of the turbulent fluctuating motion, which qualifies this approach as a highly reliable candidate for providing a sufficiently accurate level of description of the flow induced generation of sound.
Technical Paper

Extended Solution of a Trimmed Vehicle Finite Element Model in the Mid-Frequency Range

2020-09-30
2020-01-1549
The acoustic trim components play an essential role in Noise, Vibration and Harshness (NVH) behavior by reducing both the structure borne and airborne noise transmission while participating to the absorption inside the car and the damping of the structure. Over the past years, the interest for numerical solutions to predict the noise including trim effects in mid frequency range has grown, leading to the development of dedicated CAE tools. Finite Element (FE) models are an established method to analyze NVH problems. FE analysis is a robust and versatile approach that can be used for a large number of applications, like noise prediction inside and outside the vehicle due to different sources or pass-by noise simulation. Typically, results feature high quality correlations. However, future challenges, such as electric motorized vehicles, with changes of the motor noise spectrum, will require an extension of the existing approaches.
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