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Technical Paper

Research on acceleration slip regulation for battery electric vehicle

2024-09-08
2024-01-3051
As an important part of the automotive electronic control system, the acceleration slip regulation takes the tire slip rate as the main control target. By controlling the wheel driving force, the tire maintains a stable adhesion state to obtain good handling stability and power.This paper takes electric vehicles with independent front and rear axles as the research object, and studies the application of acceleration slip regulation in vehicle drive control.At present, the main technologies for acceleration slip regulation of electric vehicles include: logic threshold control, PID control, sliding mode control and fuzzy control. Since the car is a complex and changeable system, using one of the above methods alone to control car slippage may not yield ideal results.
Technical Paper

Comprehensive Study on Challenges to introduce AEBS feature in Indian Perspective

2024-09-08
2024-01-3050
India is a diverse country in terms of road conditions, road maintenance, traffic conditions, traffic density, quality of traffic which implies presence of agricultural tractors, bullock carts, autos, motor bikes, oncoming traffic in same lane, vulnerable road users (VRU) walking in the same lanes as vehicles, VRU’s crossing roads without using zebra crossings etc. as additional traffic quality deterrents in comparison to developed countries. The braking capacity of such vivid road users may not be at par with global standards due to their categories, maintenance, loading beyond specifications, driver behavior which includes the tendency to maintain a close gap between the preceding vehicle etc. which may lead to incidents specifically of rear collisions due to the vehicle going through an emergency braking event.
Technical Paper

Analysis of Stick-Slip Phenomenon During Creep Groan Using Acoustic Emission Sensing

2024-09-08
2024-01-3033
When the brakes are released and the vehicle starts on a slope, the brakes and suspensions vibrate and the car body resonates, generating a noise between 10 to 300 Hz, which is called brake creep groan. This low-frequency noise is more likely to occur in high-humidity environments. As vehicles become quieter with the introduction of EVs, improving this low-frequency noise has become an important issue. It is known that the excitation force is the stick-slip between the brake rotor and pads, but there are few studies that directly analyze stick-slip occurring in a vehicle. Acoustic emission (AE) is a phenomenon in which strain energy stored inside a material is released as elastic stress waves, and AE sensing can be used to elucidate the friction phenomena. In this study, the AE sensing is used to analyze changes in the stick-slip occurrence interval and generated energy when creep groan occurs. As a result, it was confirmed that the AE signal increased with high humidity.
Technical Paper

Comprehensive Methodology for Quantitative Prediction and Experimental Validation of Brake Rattle Noise Across Diverse Mounting Orientations of Disc Brake System

2024-09-08
2024-01-3034
In the automotive industry, Noise-Vibration-Harshness (NVH) performance has undergone significant evolution, transitioning from merely meeting performance requirements to prioritizing user comfort. Specifically, within the realm of vehicle NVH, various areas such as drivetrain, wind noise, engine noise, and brake noise have garnered attention. While older vehicles primarily emphasized performance needs, modern automotive design increasingly revolves around ensuring user comfort and satisfaction. One notable aspect of NVH improvement lies in brake systems, where manufacturers are now engineering products to meet stringent Original Equipment Manufacturer (OEM) criteria. This focus on enhancing brake NVH aims to enhance user comfort and ultimately boost customer satisfaction. The rise of electric vehicles, characterized by their minimal engine noise (around 40 – 50 dB), has accentuated the significance of reducing noise generated by brake systems, particularly rattle noise.
Technical Paper

Time for a Model Change – Inorganic Friction Materials

2024-09-08
2024-01-3042
Abstract: The following presentation would like to draw the attention to alternative friction lining formulations based on inorganic binders which can result in new, future-proof friction lining materials. First characterizing tests of the new inorganic friction materials (IFM) can give an overview of the capabilities and potentials. Dyno-tests have been carried out on passenger cars as well as commercial vehicle brakes. The aspects of high-temperature stability in the fading tests of the AKM- and AMS tests and the incombustible nature of the binder, as well as the reduction in PM10 emissions compared to classic organic friction materials, make these materials particularly fascinating for applications in passenger car as well as in commercial vehicle applications.
Technical Paper

Enhancing Brake Performance: FNC-Smart-ONC® Technology to address corrosion challenges and extend the durability of GCI rotors.

2024-09-08
2024-01-3044
The most used rotor material is gray cast iron (GCI), known for its susceptibility to corrosion. The impact of corrosion on the braking system is paramount, affecting both braking performance and the emission of particulate matter. The issue becomes more severe, especially when the brakes are left stationary or unused for extended durations in humid conditions, as seen with electric vehicles. Brake disc corrosion not only diminishes braking effectiveness but also amplifies the risk of corrosion adhesion between contacting surfaces, leading to substantial damage and an increase in the quantity and mass of non-exhaust particulate emissions. The friction material of brake pads plays a crucial role in generating the necessary stopping force, creating friction that transforms kinetic energy into heat. However, heightened pressure during braking elevates rotor temperatures, contributing to the degradation of the friction material.
Technical Paper

An Archive-based Micro Genetic Algorithm Approach for Optimizing Wheel Bearing Performance and Reducing Friction

2024-09-08
2024-01-3046
Cars and vans are accountable for 14.5% of the total CO2 emissions in the European Union [1], exerting a significant impact on public health and the environment. To align with the climate objectives set by the Council and the European Parliament, the Fit for 55 package encompasses a series of proposals aimed at revising and modernizing EU legislation while introducing new initiatives. The ultimate goal is to ensure that EU policies are in harmony with the climate targets, specifically the EU's aspiration to reduce greenhouse gases (GHGs) by at least 55% by 2030 compared to 1990 levels and achieve climate neutrality by 2050.To meet the fleet average emissions targets, automotive Original Equipment Manufacturers (OEMs) are compelled to reduce emissions from their vehicles by addressing various components.
Technical Paper

Evaluation of friction torque in tapered roller bearings

2024-09-08
2024-01-3047
A bearing is a mechanical component that facilitates rotation and supports loads. Bearings are differentiated into ball bearings and tapered roller bearings, depending on the rotating mechanism. Tapered roller bearings, known for their superior load-bearing capabilities compared to ball bearings, are utilized in high-load applications such as commercial vehicle and truck wheel bearings, aircraft and high-speed train components, and heavy machinery spindles. With the growing emphasis on CO2 emission reduction and fuel efficiency in the automotive industry, there's an increasing demand to minimize driving friction torque. This has highlighted the importance of research into the driving friction torque of bearings. Although numerous studies have explored lubrication, friction, and contact phenomena in tapered roller bearings, including aspects like lip friction and roller misalignment and skew, investigations into the effects of roller shape and material properties have been limited.
Technical Paper

Optimization-Based Battery Thermal Management for Improved Regenerative Braking in CEP Vehicles

2024-07-02
2024-01-2974
The courier express parcel service industry (CEP industry) has experienced significant changes in the recent years due to increasing parcel volume. At the same time, the electrification of the vehicle fleets poses additional challenges. A major advantage of battery electric CEP vehicles compared to internal combustion engine vehicles is the ability to regenerate the kinetic energy of the vehicle in the frequent deceleration phases during parcel delivery. If the battery is cold the maximum recuperation power of the powertrain is limited by a reduced chemical reaction rate inside the battery. In general, the maximum charging power of the battery depends on the state of charge and the battery temperature. Due to the low power demand for driving during CEP operation, the battery self-heating is comparably low under cold ambient conditions. Without active conditioning of the battery, potential regenerative energy is lost as a result of the cold battery.
Technical Paper

Reduction of Flow-induced Noise in Refrigeration Cycles

2024-07-02
2024-01-2972
In electrified vehicles, auxiliary units can be a dominant source of noise, one of which is the refrigerant scroll compressor. Compared to vehicles with combustion engines, e-vehicles require larger refrigerant compressors, as in addition to the interior, also the battery and the electric motors have to be cooled. Currently, scroll compressors are widely used in the automotive industry, which generate one pressure pulse per revolution due to their discontinuous compression principle. This results in speed-dependent pressure fluctuations as well as higher-harmonic pulsations that arise from reflections. These fluctuations spread through the refrigeration cycle and cause the vibration excitation of refrigerant lines and heat exchangers. The sound transmission path in the air conditioning heat exchanger integrated in the dashboard is particularly critical. Various silencer configurations can be used to dampen these pulsations.
Technical Paper

Thermal Management System for Battery Electric Heavy-Duty Trucks

2024-07-02
2024-01-2971
On the path to decarbonizing road transport, electric commercial vehicles will play a significant role. The first applications were directed to the smaller trucks for distribution traffic with relatively moderate driving and range requirements, but meanwhile, the first generation of a complete portfolio of truck sizes is developed and available on the market. In these early applications, many compromises were accepted to overcome component availability, but meanwhile, the supply chain can address the specific needs of electric trucks. With that, the optimization towards higher usability and lower costs can be moved to the next level. Especially for long-haul trucks, efficiency is a driving factor for the total costs of ownership. Besides the propulsion system, all other systems must be optimized for higher efficiency. This includes thermal management since the thermal management components consume energy and have a direct impact on the driving range.
Technical Paper

Analysis of human driving behavior with focus on vehicle lateral control

2024-07-02
2024-01-2997
The optimization and further development of automated driving functions offers great potential to relieve the driver in various driving situations and increase road safety. Simulative testing in particular is an indispensable tool in this process, allowing conclusions to be drawn about the design of automated driving functions at a very early stage of development. In this context, the use of driving simulators provides support so that the driving functions of tomorrow can be experienced in a very safe and reproducible environment. The focus of the acceptance and optimization of automated driving functions is particularly on vehicle lateral control functions. As part of this paper, a test person study was carried out regarding manual vehicle lateral control on the dynamic vehicle road simulator at the Institute of Automotive Engineering.
Technical Paper

What is going on around the Automotive PowerNet - An overview of state-of-the-art PowerNet, insights into the new trends, and a simulation solution to keep pace with architectural changes.

2024-07-02
2024-01-2985
The automotive PowerNet is facing a major transformation. The three main drivers are: • Increasing power • Availability requirements • PowerNet complexity and cost reduction These driving factors result in a wide variety of possible future PowerNet topologies. The increasing power demand is among others caused by the progressive electrification of formerly mechanical components and the trend of increasing number of comfort loads. This leads to a steady increase in installed electrical power. X-by-wire systems and autonomous driving functions result in higher availability requirements. As a result, the power supply of all safety-critical loads must always be kept sufficiently stable. To reduce costs and increase reliability, the car manufacturers aim to reduce the complexity of the PowerNet System, including the wiring harness and the controller network. The wiring harness e.g., is currently one of the costliest parts of modern cars. These challenges are met with different concepts.
Technical Paper

Graph based cooperation strategies for automated vehicles in mixed traffic

2024-07-02
2024-01-2982
In the context of urban smart mobility, vehicles have to communicate with each other, surrounding infrastructure, and other traffic participants. By using Vehicle2X communication, it is possible to exchange the vehicles’ position, driving dynamics data, or driving intention. This concept yields the use for cooperative driving in urban environments. Based on current V2X-communication standards, a methodology for cooperative driving of automated vehicles in mixed traffic scenarios is presented. Initially, all communication participants communicate their dynamic data and planned trajectory, based on which a prioritization is calculated. Therefore, a decentralized cooperation algorithm is introduced. The approach is that every traffic scenario is translatable to a directed graph, based in which a solution for the cooperation problem is computed via an optimization algorithm.
Technical Paper

FMCW Lidar Simulation with Ray Tracing and Standardized Interfaces

2024-07-02
2024-01-2977
In pursuit of safety validation of automated driving functions, efforts are being made to accompany real world test drives by test drives in virtual environments. To be able to transfer highly automated driving functions into a simulation, models of the vehicle’s perception sensors such as lidar, radar and camera are required. In addition to the classic pulsed time-of-flight (ToF) lidars, the growing availability of commercial frequency modulated continuous wave (FMCW) lidars sparks interest in the field of environment perception. This is due to advanced capabilities such as directly measuring the target’s relative radial velocity based on the Doppler effect. In this work, an FMCW lidar sensor simulation model is introduced, which is divided into the components of signal propagation and signal processing. The signal propagation is modeled by a ray tracing approach simulating the interaction of light waves with the environment.
Technical Paper

Charging infrastructure for employer parking – Real data analysis and charging algorithms for future customer demands

2024-07-02
2024-01-2980
The mobility industry and the entire ecosystem is currently striving towards sus-tainable mobility which leads to continuous production ramp-up of electrified vehicles. The parallel increase of the charging infrastructure is faced with various challenges regarding needed investments and the connection into the electricity grid. MAHLE chargeBIG offers centralized and large scaled charging infrastruc-ture with more than 1,800 already installed charging points. This presentation and paper is evaluating the functionality of the system by ana-lyzing backend real data of various employer parking installations. It can be shown and proven that a single-phase charging concept is sufficient and able to manage most customer relevant charging events by considering the needs and limitations of the related electricity grid infrastructure. Smart charging algorithms enable the integration of the charging infrastructure in smart grid company environments.
Technical Paper

Standardized Differential Inductive Positioning System for Wireless Charging of Electric Vehicles

2024-07-02
2024-01-2987
To shape future mobility MAHLE has committed itself to foster wireless charging for electrical vehicles. The standardized wireless power transfer of 11 kW at a voltage level of 800 V significantly improves the end user experience for charging an electric vehicle without the need to handle a connector and cable anymore. Combined with automated parking and autonomous driving systems, the challenge to charge fleets without user interaction is solved. Wireless charging is based on inductive power transfer. In the ground assembly’s (GA) power transfer coil, a magnetic field is generated which induces a voltage in the vehicle assembly (VA) power transfer coil. To transfer the power from grid to battery with a high efficiency up to 92% the power transfer coils are compensated with resonant circuits. In this paper the Differential-Inductive-Positioning-System (DIPS) to align a vehicle on the GA for parking will be presented.
Technical Paper

Enhancing BEV Energy Management: Neural Network-Based System Identification for Thermal Control Strategies

2024-07-02
2024-01-3005
Modeling thermal systems in Battery Electric Vehicles (BEVs) is crucial for enhancing energy efficiency through predictive control strategies, thereby extending vehicle range. A major obstacle in this modeling is the often limited availability of detailed system information. This research introduces a methodology using neural networks for system identification, a powerful technique capable of approximating the physical behavior of thermal systems with minimal data requirements. By employing black-box models, this approach supports the creation of optimization-based operational strategies, such as Model Predictive Control (MPC) and Reinforcement Learning-based Control (RL). The system identification process is executed using MATLAB Simulink, with virtual training data produced by validated Simulink models to establish the method's feasibility. The neural networks utilized for system identification are implemented in MATLAB code.
Technical Paper

Probabilistically Extended Ontologies a basis for systematic testing of ML-based systems

2024-07-02
2024-01-3002
Autonomous driving is a hot topic in the automotive domain, and there is an increasing need to prove its reliability. They use machine learning techniques, which are themselves stochastic techniques based on some kind of statistical inference. The occurrence of incorrect decisions is part of this approach and often not directly related to correctable errors. The quality of the systems is indicated by statistical key figures such as accuracy and precision. Numerous driving tests and simulations in simulators are extensively used to provide evidence. However, the basis of all descriptive statistics is a random selection from a probability space. The difficulty in testing or constructing the training and test data set is that this probability space is usually not well defined. To systematically address this shortcoming, ontologies have been and are being developed to capture the various concepts and properties of the operational design domain.
Technical Paper

Electromagnetic Compatibility Assessment of Electric Vehicles During DC-Charging with European Combined Charging System

2024-07-02
2024-01-3008
The ongoing energy transition will have a profound impact on future mobility, with electrification playing a key role. Battery electric vehicles (EVs) are the dominant technology, relying on the conversion of alternating current (AC) from the grid to direct current (DC) to charge the traction battery. This process involves power electronic components such as rectifiers and DC/DC converters operating at high switching frequencies in the kHz range. Fast switching is essential to minimize losses and improve efficiency, but it might also generate electromagnetic interferences (EMI). Hence, electromagnetic compatibility (EMC) testing is essential to ensure reliable system operations and to meet international standards. During DC charging, the AC/DC conversion takes place off-board in the charging station, allowing for better cooling and larger components, resulting in increased power transfer, currently up to 350 kW.
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