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When the brakes are released and the vehicle starts, the brakes and suspensions vibrate and the car body resonates at 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. Furthermore, the friction phenomena during creep
Toyoda, HajimeYazawa, YusukeArai, ShinichiOno, ManabuHara, YasuhiroHase, Alan
Brake caliper commonly utilizes rubber or spring components to maintain specific clearance range for sliding characteristics, rendering them susceptible to rattle noise. The Electro-Mechanical Brake (EMB) caliper has attracted attention for its advantageous features such as reduced brake drag, optimized vehicle layout, and precise brake control. However, the inclusion of additional components related to the dry-type pressurizing system results in increased caliper weight and susceptibility to rattle noise. This study thoroughly examines rattle noise characteristics in our prototype EMB caliper, identifying primary noise sources on the piston and guide-pin sides. Implementing piston seals and guide-pin boots tightening force proves the effectiveness in improving rattle noise characteristics. Collisions between the piston and ball-screw head can be mitigated by piston inner seal, significantly reducing rattle noise. The effectiveness of the piston outer seal is limited and can be
Yoon, BoramJeon, Kyeong HunBoo, SangpilShin, ChoongsikKim, Tae Hoon
The once rarified field of Artificial Intelligence, and its subset field of Machine Learning have very much permeated most major areas of engineering as well as everyday life. It is already likely that few if any days go by for the average person without some form of interaction with Artificial Intelligence. Inexpensive, fast computers, vast collections of data, and powerful, versatile software tools have transitioned AI and ML models from the exotic to the mainstream for solving a wide variety of engineering problems. In the field of braking, one particularly challenging problem is how to represent tribological behavior of the brake, such as friction and wear, and a closely related behavior, fluid consumption (or piston travel in the case of mechatronic brakes), in a model. This problem has been put in the forefront by the sharply crescendo-ing push for fast vehicle development times, doing high quality system integration work early on, and the starring role of analysis-based tools in
Antanaitis, David
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 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 front vehicle going through an emergency braking event. The following paper provides a comprehensive study of the special considerations or intricacies in implementation of Autonomous Emergency Braking (AEBS) feature into Indian traffic
Kartheek, NedunuriKhare, RashmitaSathyamurthy, SainathanManickam, PraveenkumarKuchipudi, Venkata Sai Pavan
This is a case study to cope with the brake dust regulation of EURO7, countermeasures were listed, and evaluation and verification studies using C segment sports utility vehicle were conducted on them. Through this phase1 study, it was most reasonable to apply hard metal cladding disks and metallic friction material to front brake and apply friction materials as NAO with less dust generation to rear brake. This was because it is possible to satisfy new regulations without deteriorating the required performance in Europe. However, it is necessary to develop detailed specifications of discs and friction materials to satisfy our braking development goals for European models in the Phase 2
Kim, Yoon CheolKim, Jwa Kyum
A bearing is a mechanical component that transmits rotation and supports load. Depending on the type of rotating mechanism, bearings are categorized into ball bearings and tapered-roller bearings. Tapered-roller bearings are superior to ball bearings in load-bearing capabilities. They are used in applications where high loads, such as, the wheel bearings for commercial vehicles and trucks, aircraft, high-speed trains, and heavy-duty spindles for heavy machinery must be supported. The demand for reducing the friction torque in automobiles has recently increased owing to carbon-emission regulations and fuel-efficiency requirements. Therefore, research on the friction torque of bearings is essential; studies have been conducted on lubrication, friction, and contact in tapered-roller bearings. There have also been studies on lip friction, roller misalignment, and so on; however, research on the influence of roller geometries and material properties is scarce. This study investigated the
Lee, SeungpyoAn, Hyun Gyu
Cars and vans are accountable for 14.5% of the total CO2 emissions in the European Union, 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. The urgent need for car makers to reduce their carbon footprint, combined with the imperative to improve the mileage range of electric vehicles, has led to the creation of a novel
Bogliacino, FabioRe, PaoloFerrero, Alessandro
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 (EVs). Brake disc corrosion amplifies the risk of corrosion adhesion between contacting surfaces, leading to substantial damage, increased quantity and mass of non-exhaust particulate emissions, and decreased braking effectiveness. In addition, brake pads' friction material 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. This degradation manifests in decreased mechanical strength, heightened
Nousir, SaadiaWinter, Karl-Michael
To combat corrosion and wear issues of automotive brake discs, many manufacturers have introduced various surface treatment technologies, such as thermal spraying, laser cladding, and ferritic nitrocarburizing (FNC). Besides those surface treatment technologies, a plasma electrolytic aluminating (PEA) process has also shown to be effective in producing alumina-based ceramic coatings on cast iron substrates, providing an enhanced corrosion resistance. In this study, the PEA-coated brake rotor and FNC-treated brake rotor were comparatively tested in various corrosion conditions, including an electrochemical corrosion test and simulative corrosion experiment, before and after a road driving test. A scanning electron microscope (SEM) and an energy-dispersive X-ray (EDX) were used to observe and analyze morphology and chemical compositions of the surfaces and cross-sections of the tested rotors. The results showed that the new PEA-coated brake rotor demonstrated the best corrosion
Liu, YintingNie, Xueyuan
The influence of moisture adsorption, prior braking, and deceleration rate on the low-speed braking noise has been investigated, using copper-free disc pads on a passenger car. With increasing moisture adsorption time, decreasing severity of prior braking or increasing deceleration rate, the noise sound level increases for the air-borne exterior noise as well as for the structure-borne interior noise. The near-end stop noise and the zero-speed start-to-move noise show a good correlation. Also, a good correlation is found between the noise measured on a noise dynamometer and on a vehicle for the air-borne noise. All the variables need to be precisely controlled to achieve repeatable and reliable results for dynamometer and vehicle braking groan noise tests. It appears that the zero-speed start-to-move vehicle interior noise is caused by the pre-slip vibration of the brake: further research is needed
Sriwiboon, MeechaiRhee, Seong KwanSukultanasorn, JittrathepKunthong, Jitpanu
Moisture adsorption and compression deformation behaviors of Semimet and Non-Asbestos Organic brake pads were studied and compared for the pads cured at 120, 180 and 240 0C. The 2 types of pads were very similar in moisture adsorption behavior despite significant differences in composition. After being subjected to humidity and repeated compression to 160 bars, they all deform via the poroviscoelastoplastic mechanism, become harder to compress, and do not fully recover the original thickness after the pressure is released for 24 hours. In the case of the Semimet pads, the highest deformation occurs with the 240 °C-cure pads. In the case of the NAO pads, the highest deformation occurs with the 120 0C-cure pads. In addition, the effect of pad cure temperatures and moisture adsorption on low-speed friction was investigated. As pad properties change all the time in storage and in service because of continuously changing humidity, brake temperature and pressure, one must question any
Rhee, Seong KwanRathee, AmanSingh, ShivrajSharma, Devendra
This paper’s aim is to explain alternative friction lining formulations based on inorganic polymer binders for the production of new, future-proof brake friction materials. The aspects of high-temperature stability in the fading tests of the AKM- and AMS tests, as well as the reduction in PM10 emissions compared to classic organic friction materials, make these materials particularly fascinating for future use. Additionally, the energy savings potential of this type of friction lining could be of particular importance when sustainability considerations further influence our development activities in friction brake related applications
Milczarek, Roman PaulWittig, Niels
The squeal noise is one of the critical factors to qualify a disc brake design from the Noise Vibration and Harshness (NVH) perspective. It is imperative to be watchful of the unstable natural modes of the brake assembly which trigger squeal. Any design modification for reducing a part’s contribution to targeted squeal mode can adversely affect and give rise to new squeal modes. Also, controlling conflicting requirements like mass, strength, and casting manufacturability, further adds up complexity, which increases design iterations and product cost. In view of these challenges, the application of the topological optimizations embedded under an artificial intelligence (AI) driven optimization workflow is explored. The scope of optimization is kept limited only to the caliper. Complex eigenvalue (EV) finite element analysis (FEA) of baseline design brake assembly is performed which predicts critical squeal mode having 34% strain energy contribution from caliper. To improve the squeal
Kumar, DineshInoue, HayuruYamamoto, MasayukiKhare, PrashantKasahara, TeruyasuHasegawa, Keita
The work investigates the penetration depth of a low environmental impact Cr(III)-based sealing on two anodized Aluminum-Silicon alloys (i.e., EN AC-42200 and EN AC-43200) for brake system applications. EN AC-42200 and EN AC-43200 specimens are: 1) obtained by sectioning of gravity cast components; 2) anodized using different process times to obtain different anodic layer thicknesses; and 3) sealed in a Cr(III)-based proprietary sealing solution at low temperature. The obtained sealed anodic layers are characterized using several techniques including: Glow Discharge Optical Emission Spectroscopy (GDOES), metallographic analyses and Eddy current thickness measurements. Results demonstrate that: a) the Cr(III) concentration within the anodic layers shows an exponentially decreasing trend from the specimen surface toward the anodic layer-substrate interface; b) the typical thickness of the sealing layer is in the order of 1.5μm; and c) the Cr(III) penetration depth is only marginally
Pavesi, AriannaFumagalli, LucaAbello, Mary AngelBonfanti, AndreaMancini, AlessandroVedani, MaurizioBertasi, Federico
On one hand, simulation tools are widely used to study and examine new technologies before building prototypes. It is a cost and time saver if it is mathematically modeled with and simulated in real time with sufficient fidelity. On the other hand, the expansion of electric and hybrid vehicle development requested advancing the Electronic Brake Booster (EBB) technologies. In this paper, a simulation tool for the EBB is developed to simulate the performance in real time with a very quick response compared to the previous models with a novel fuzzy logic control (FLC) for the position tracking control. The configuration of the EBB is established, and the system model, including the permanent magnet synchronous motor (PMSM), a double reduction transmission (gears and a ball screw), a servo body, a reaction disc, and the hydraulic load, is modeled. The load-dependent friction has been compensated by using the Karnopp-friction model. FLC has been used for the control algorithm. The control
Soliman, Amr M.E.Kaldas, Mina M.Soliman, Aref M.A.Huzayyin, Ahmed
As an important part of the automobile 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 driving stability and power. This paper takes battery electric vehicles as the research object and explores the application of acceleration slip regulation in vehicle drive control. In order to obtain the true vehicle speed when the wheel slips, a vehicle speed observer based on extended Kalman Filter is proposed. Secondly, this paper designs a road surface recognition method based on fuzzy theory, which obtains the optimal slip rate under current road conditions by taking the actual slip rate and road surface adhesion coefficient as input. When a vehicle is driving on a road with different adhesion coefficients on the left and right sides, one side of the wheel may slip severely while the opposite side wheel does not slip. In order to
Kang, KaileiLiu, XingchenLiu, XinHong
Wheel bearings play a critical role in providing smooth rotation when vehicles move in straight line and turning motions. If a wheel bearing catastrophically fails, there is the possibility of vehicle damage or even personal injury. Since this is the case, wheel bearings require a higher level of reliability and robustness. With the drive towards a carbon neutral society against the background of global warming in recent years, the demand for lightweighting and lower friction for wheel bearings has become a priority. Weight reductions will cause larger deformation of each bearing component, and especially raceway deformation of the outer ring will impact bearing life. Therefore, optimization of the outer ring geometry is required to meet bearing life requirements and to achieve a lightweight design. In this research, we clarified not only the relationship between outer ring raceway deformation and multiple outer ring geometries under turning load using FEM (Finite Element Method) but
Kitada, TatsuyaSeki, MakotoImanaka, Hironori
Niobium (Nb) alloyed Grey cast iron in combination with Ferritic Nitrocarburize (FNC) case hardening heat treatment is proposed to improve wear resistance and reduce brake dust generation of brake rotors. Standard Eutectic and Hypereutectic Grey irons alloyed with Niobium were evaluated in comparison to baseline unalloyed compositions. Brake speed snub sensitivity tribological testing was performed on a matrix including Niobium alloyed, Unalloyed, FNC, Non FNC, Non-Asbestos Organic (NAO) friction and Low metallic (Low Met) friction materials. Full size brake rotors were evaluated by Block Wear and Corrosion Cleanability. Improved wear, corrosion resistance and reduced brake dust debris were demonstrated by the Niobium alloyed FNC brake rotor combinations. Corrosion is an important consideration when evaluating brake performance. Combining cyclic corrosion and brake rotor testing provides the best comparison with field exposure
Holly, Mike
Many performance sport passenger vehicles use drilled or grooved cast iron brake rotors for a better braking performance or a cosmetic reason. Such brake rotors would unfortunately cause more brake dust emission, appearing with dirty wheel rims. To better understand the effects of such brake rotors on particle emission, a pin-on-disc tribometer with two particle emission measurement devices was used to monitor and collect the emitted airborne particles. The first device was an aerodynamic particle sizer, which is capable of measuring particles ranging from 0.5 to 20 μm. The second device was a condensation particle counter, which measures and collects particles from 4 nm to 3 μm. The testing samples were scaled-down brake discs (100 mm in diameter) against low-metallic brake pads. Two machined surface conditions (plain and grooved) with uncoated or ceramic-coated friction surfaces were selected for the investigation. The results showed that the grooved friction surface led to a higher
Cai, RanNie, XueyuanLyu, YezheWahlstrom, Jens
Recently, the increasing complexity of systems and diverse customer demands have necessitated the development of highly efficient vehicles. The ability to accurately predict vehicle performance through simulation allows for the determination of design specifications before the construction of test vehicles, leading to reduced development schedules and costs. Therefore, detailed brake thermal performance predictions are required both for the front and rear brakes. Moreover, scenarios requiring validation, such as alpine conditions that apply braking severity to xEV with the regenerative braking system, have become increasingly diverse. To address this challenge, this study proposes a co-simulation method that incorporates a machine-learned brake pad friction coefficient prediction model to enhance the accuracy of brake thermal capacity predictions within the vehicle simulation environment. This innovative method allows for the simultaneous prediction of both front and rear-wheel brakes
Cho, SunghyunBaek, SangHeumKim, Min SooHong, IncheolKim, Hyun KiKim, GwichulLee, Jounghee
Brake drag in disc brakes occurs during the off-brake-phase, when the brake is not applied but friction contacts between brake disc and pads persist. First and foremost, the resulting drag torque increases energy consumption, where a few Newton meters can have a significant impact on the crucial factor – range – of battery-electric-vehicles. Moreover, brake wear is accelerated in conjunction with enlarged taper-wear of the pads. Additional wear can also imply increased brake particle emissions which are going to be limited by upcoming regulations due to their potential health risk. In this light different countermeasures aim to create and maintain a sufficient air gap between brake disc and pads when the brake is released to avoid residual friction contacts. Among others these include optimization of piston retraction by adjusting the seal-grooves and integrating pad springs into the caliper to push the pads back. State of the art to analyze the effectiveness of countermeasures are
Huchtkoetter, PhilippNeubeck, JensWagner, Andreas
Brake squeal is a phenomenon caused by various factors such as stiffness of brake components, mode coupling, friction coefficient, friction force variation, pressure, temperature and humidity. FEA simulation is effective at predicting and investigating the cause of brake squeal, and is widely used. However, in many FEA simulations, models of brake lining are mostly a brand-new shaper, so that the change of pressure distribution or pad shape, which can occur due to the lining wear, are not taken account. In this research, brake squeal analysis was conducted with consideration of lining wear, applying Fortran codes for Abaqus user subroutine. The brake assembly model for the analysis is created by using a 3D scanner and has a close shape to the real one. The wear patterns calculated by the analysis are similar to those of brake pads after a noise test. The complex eigenvalue analysis shows two unstable modes at the frequency of squeal occurred in the noise test. One is out-of-plane
Ikegami, TokunosukeMillsap, TomYamaguchi, Yoshiyuki
The assessment of brake friction materials extends beyond squeal noise and thermal roughness testing as it play crucial role in other brake noise phenomena such as creep groan and dynamic grunt. These low frequency noise types are significant as they directly affect passengers comfort levels. Creep groan noise defined as audible stick-slip noise at low vehicle speed during partial brake application, typically encountered in dense traffic conditions. Dynamic grunt is another form of stick-slip noise observed during high-speed braking and it is noticeable just prior to vehicle’s complete stop. This noise is indicative of frictional interaction between the brake pad and disc under deceleration scenario. Comparative analysis of two distinct brake friction materials was conducted utilizing both NVH dynamometer and real-world vehicle testing. The NVH dynamometer procedure was designed to evaluate the creep groan and dynamic grunt phenomena under controlled environmental conditions. For the
Barot, AnkitWang, Weicherng
Toward the goal of “dual carbon economy” development, new energy hybrid commercial vehicles have become the main vehicles to meet the future fuel consumption and emission targets. In order to meet the high requirements of commercial vehicles on power and to minimize the influence of ambient temperature on the power of the vehicle, this study proposes a composite energy storage system (CESS) incorporating ultracapacitors. To further understand the impact of ultracapacitor on the dynamic performance of the vehicle, this study compares the dynamics of series range-extended hybrid pickup trucks with and without ultracapacitor at ambient and low temperatures, as well as the effect of ultracapacitor on the service life of lithium-ion batteries, by means of simulation. The results show that at room temperature (25°C), the addition of ultracapacitor shortens the 0–100 km/h acceleration time of the whole vehicle by 24.4% and improves the off-road climbing performance by 11.7%; at low
Yu, Xiaocao
This article proposes a new model for a cooperative and distributed decision-making mechanism for an ad hoc network of automated vehicles (AVs). The goal of the model is to ensure safety and reduce energy consumption. The use of centralized computation resource is not suitable for scalable cooperative applications, so the proposed solution takes advantage of the onboard computing resources of the vehicle in an intelligent transportation system (ITS). This leads to the introduction of a distributed decision-making mechanism for connected AVs. The proposed mechanism utilizes a novel implementation of the resource-aware and distributed–vector evaluated genetic algorithm (RAD-VEGA) in the vehicular ad hoc network of connected AVs as a solver to collaborative decision-making problems. In the first step, a collaborative decision-making problem is formulated for connected AVs as a multi-objective optimization problem (MOOP), with a focus on energy consumption and collision risk reduction as
Ghahremaninejad, RezaBilgen, Semih