Abstract Brake squeal reduces comfort for the vehicle occupants, damages the reputation of the respective manufacturer, and can lead to financial losses due to cost-intensive repair measures. Mode coupling is mainly held responsible for brake squeal today. Two adjacent eigenfrequencies converge and coalesce due to a changing bifurcation parameter. Several approaches have been developed to suppress brake squeal through structural changes. The main objective is to increase the distance of coupling eigenfrequencies. This work proposes a novel approach to structural modifications and sizing optimization aiming for a start at shifting a single component eigenfrequency. Locations suitable for structural changes are derived such that surrounding modes do not significantly change under the modifications. The positions of modifications are determined through a novel sensitivity calculation of the eigenmode to be shifted in frequency. In the present work, the structural changes are carried out

Deutzer, Marcel, Stender, Merten, Tüpker, Nicolas, Hoffmann, Norbert

Kinetics of Moisture Adsorption and Its Impact on Brake Pad Compression Modulus and Compressibility: Compression Modulus vs. Dynamic Modulus and Friction Variation

2022-01-116509/19/2022

The kinetics of moisture adsorption is studied for copper-free brake pads. The pad weight gain is found to increase linearly with the square root of exposure time to humidity at a given temperature – the higher the humidity, the higher the weight gain. As the moisture content in the pad increases, the tangent modulus increases while the secant modulus decreases, resulting in decreasing compressibility associated with the tangent modulus of compression and increasing compressibility associated with the secant modulus of compression – compressibility defined as a reciprocal of compression modulus. Compression modulus and dynamic modulus are compared, and implications for friction coefficient variation are discussed. A rate constant of adsorption is proposed to define and compare moisture sensitivity of friction materials.

Rhee, Seong Kwan, Rathee, Aman, Singh, Shiv Raj, Sharma, Devendra

The Effects Of Corrosion On Particle Emissions From A Grey Cast-Iron Brake Disc

2022-01-117809/19/2022

Reducing exhaust emissions has been a major focus of research for a number of years since internal combustion engines (ICE) contribute to a large number of harmful particles into the environment. As a way of reducing emissions and helping to tackle climate change, many countries are announcing that they will ban the sale of new ICE vehicles soon. Electrical vehicles (EVs) represent a popular alternative vehicle propulsion system. However, although they produce zero exhausted emissions, there is still a concern of the non-exhausted emission, such as brake dust, which can still cause harm to human health and the environment. Despite EVs primarily using regenerative braking, they still require friction brakes to supplement as and when required. Moreover, EV’s will likely continue to use the traditional grey cast iron brake rotor, which is heavy and prone to corrosion which may exacerbate the brake wear emissions. This study concentrates on emissions from a conventional grey cast iron

Ghouri, Ishmaeel, Barker, Richard, Kosarieh, Shahriar, Brooks, Peter, Barton, David

Brake Pad Wear Monitor using MOC(Motor On Caliper) EPB ECU

2022-01-116709/19/2022

With the spread of new trends such as autonomous driving and vehicle subscription service, drivers may pay less attention to the maintenance of the vehicle. Brake pads being safety critical components, a wear indicator is required by the regulation. Current application of the wear indicator in the market uses whether sound generating metal strip or wire harness based pad wear sensor. The former is not effective in generating clear alarm to the driver, and the latter is now cost effective, and there is a need for more effective and low cost solution. In this paper, a pad wear monitoring system using MOC(Motor On Caliper) EPB(Electric Parking Brake) ECU is proposed. An MOC EPB is equipped with a motor, geartrain and an ECU. The motor current when applying the parking brake is influenced by the mechanical load at the brake pad side of the system. So, by analyzing the time history of the current it is possible to measure the clearance between brake pad and disc induced by the pad wear

Lee, Soohyuk

Effect of Humidity Levels on the Compressibility of Automotive Brake Friction Materials

2022-01-116409/19/2022

The load-deflection relationship of automotive brake friction materials (also known as “compressibility”) is a characteristic which may both influence and advise as to brake performance, including driver experience, noise and vibration behavior, and manufacturer quality control. It has been reported that changes in environmental humidity may significantly alter friction material compressibility in a formulation-dependent fashion – effects which are important considerations for testing protocols and real-world applicability. Greening’s presentation includes a rigorous investigation of humidity-dependent properties across differing friction materials and manufacturers, taking advantage of the high resolution and excellent repeatability of the Greening Model 1140 Compressibility Test Machine. Sets of brake pads from (at least) two different manufacturers and of varied material type (non-asbestos organic, semi-metallic, low-metallic, etc.) will be weighed to assess changes to moisture

Sendler, Edward, Greening, Brent, Greening, Chuck

Enhancing Meta Model of the Brake Pad Friction Coefficient using the Explainable Machine Learning

2022-01-117509/19/2022

As increasing system complexity and various customer demands result in the need for highly efficient vehicle development processes. Once the brake torque is predicted accurately during the driving scenario in the earlier stage, it will be able to prevent the changing the vehicle or brake system design to satisfy the legal regulation and customer requirement. As brake torque performance target allocate brake pad friction coefficient level and characteristic, the accurate friction coefficient prediction should be preceded for accurate prediction for brake torque. Generally, the friction coefficient of the brake pad is known to vary nonlinearly depending on the physical properties of the disc and the pad, as well as the rotational speed of the brake disc, the disc temperature, and the hydraulic pressure. Furthermore, it varies depending on the driving scenario even the same condition. Therefore, there was a need for a new method : machine learning to solve this problem. A Mixed Effect

Cho, Sunghyun, Bang, Sunghoon, Jang, Jiwoo, Kim, Youngjae

Re-imagining Brake Rotor Thermal Fatigue Testing to Relate to Field Use

2022-01-116309/19/2022

The validation of brake rotors has remained, to this day, heavily reliant on “Thermal Abuse” or “Thermal Cracking” type testing, with many procedures so dated that most engineers active in the industry today cannot even recall the origin of the test. These procedures - of which there are many variants - all share the trait of greatly accelerating durability testing by performing repeated high power (high speed and high deceleration) brake applies to drive huge temperature gradients and internal stress, and often allowing the rotor to get very hot, to where the strength of the material from which the rotor is constructed is significantly degraded. There is little debate about whether these procedures work; by and large rotor durability issues in the field are extremely rare. However, without the connection to the duty cycle in the field, it is extremely difficult to interpret results (especially since many standards allow significant cracking before a failure is declared), and this can

Antanaitis, David, Langhardt, Jerry

Estimating Brake Pad Life in Regenerative Braking Intensive Vehicle Applications

2022-01-116109/19/2022

Regenerative braking without question greatly impacts brake pad service life in the field, in most cases extending it significantly. Estimating its impact precisely has not been an overriding concern - yet – due in part to the extensive sharing of brake components between regen-intensive battery-electric and hybrid vehicles, and their more friction-brake intensive internal combustion engine powered sibling. However, a multitude of factors are elevating the need for a more accurate estimation, including the emerging of dedicated electric vehicle architectures with opportunities for optimizing the friction brake design, a sharp focus on brake particulate emissions and the role of regenerative braking, a need to make design decisions for features such as corrosion protection for brake pad and pad slide components, and the emergence of driver-facing features such as Brake Pad Life Monitoring. Tackling this question raises questions such as “is the proven braking energy and temperature

Antanaitis, David, Robere, Matthew

Design, Simulation and Topology Optimization of Rotor Disc

2022-26-118805/26/2022

Brake systems are one of the most critical components of any mobile vehicle. They play a vital role in providing safety to the passengers, vehicle and surroundings. It works on basic principle of Pascals Law by applying forced frictional resistance to the rotating members of the vehicle to slow down the speed. Generally, cast iron is used as a primary material for the rotor in different applications. The current study involves the modelling of the Brake disc according to general specifications of All Terrain Vehicle and performing FEA Analysis on brake disc to study different results. The FEA analysis include the static structural to test the rigidity and ruggedness of disc, Steady and Transient Thermal Analysis to study the behavior of disc under varying thermal loads. It includes study of various parameters such as Von Mises Stress, Total Deformation, Thermal Gradient and Total Heat flux across the brake disc to evaluate the performance under extreme conditions. Different types of

Ruparelia, Rudra, Patel, Aarya, Baxi, Neel

Brake Line Repair: An Evaluation

2022-01-100103/29/2022

Brake line failures do occur, and it can happen to any vehicle. However, due to the FMVSS requirements, the brake line systems are also designed to maintain certain braking capability in the event of a brake line failure. This study was intended to further understand the effects of a brake line failure and examine the braking capability and controllability of the vehicle. A minivan was used as the test vehicle for this research. One of the brake lines of the minivan was cut and then reconnected with a compression fitting. When the compression fitting is not fully tightened, it will allow brake fluid leakage, and in the tests, the brake fluid was completely drained to simulate the empty brake fluid reservoir by repeatedly pushing the brake pedal. After the test vehicle lost all the brake fluid, braking tests were conducted. The stopping distance and the tire marks on the ground were documented. The test results show contrary to the unfounded myth that a brake line failure will result in

Arnett, Michael, Chen, H. Fred, Guenther, Dennis

Methodology and application on load monitoring using strain-gauged bolts in brake calipers

2022-01-112103/29/2022

As technology evolves, the number of sensors and available data on vehicles grow exponentially. In this context, it is essential to use sensors for monitoring key components, increasing safety and reliability, and gathering data useful for mechanical dimensioning and control systems. This paper presents an application of strain-gauged bolts brake calipers fixation of two electric vehicles. With this approach it was possible to obtain the loads applied to the brake pads and correlate them with braking behavior, therefore gaining insights on braking conditions and system state. The goal of the study is analyzing the strengths and limitations of the method and proposing developments to deploy it in real applications. This topic is particularly important and novel for electric vehicles, where powertrains can create positive and negative torques and generate complex interactions with braking system. Strain-gauges are a long-known technology applied in many fields, and its usage in bolts and

de Carvalho Pinheiro, Henrique, Sisca, Lorenzo, Carello, Massimiliana, Ferraris, Alessandro, Airale, Andrea Giancarlo, Falossi, Marco, Carlevaris, Alberto

Research on Brake Pads Particle Emissions and Temperature Reduction of a Brake Disc in Air Controlling System.

2022-01-039003/29/2022

This paper addresses the brake pad particles emitted during the braking process of a vehicle in motion. The frictional-constant contact between the disc brake and brake pads generates thermal energy as a result of increased temperature within the brake disc causing wear of the brake pads. Emission of brake pad particles into the atmosphere leads to an increase in air pollution in the environment and hence becomes hazardous to the human body. In this paper, the wheel brake disc is installed in a ventilated system where the specific airflow encompassing the disc brake accounts for thermal performance and pad particle emission from the brake pads. The mathematical model of the fundamental parameters of the brake disc and ventilation is established and the behavior of heat transfer coefficient, heat generation, heat flux, temperature rise, airflow rates, brake disc cooling time, inlet and outlet speed on the ventilation system with the brake disc are carried using computational fluid

sarvar, Yovkachov, Fayzullayevich, Jamshid Valiev

Active brake wheel cylinder pressure control based on integrated electro-hydraulic brake system

2022-01-034203/29/2022

With the development of automobile industry, the requirements of quick response, high performance are put forward for the braking system. Since the traditional braking system cannot achieve these, the international brake parts manufacturers put forward an integrated electronic braking system -the 1-Box. It can realize active braking through the servo motor. In addition, by controlling the pressure of servo cylinder and working with solenoid valves, the wheel cylinder pressure can be controlled. However, it has some problems, such as hydraulic hysteresis disturbance and complex friction obstruction, which cause obstacles to the accurate control of wheel cylinder pressure. In this paper, the active brake pressure control strategy of wheel cylinders is designed based on 1-Box. First, introduce the configuration and the working principle of wheel cylinder pressure control; Next, design the servo cylinder active brake pressure control strategy composed of servo ring and pressure ring. Servo

Zhang, Jian, Li, Linrun, Jiang, Hongwei, Liu, Qiuzheng, Wang, Yu, Yuan, Wenjian, Wu, Jian, Zhang, Xuhan

Measurement and evaluation of the conversion of thermal energy generated on the contact surface of the brake disc into electrical energy using a thermoelectric generator

2022-01-021303/29/2022

The heat generated by the friction between the brake discs and the brake pad, causes the disc’s temperature to rise which affects braking performance. This generated heat flux from the contact surface of the vehicle’s brake disc does not only affect braking performance but also tend be wasted and pollute the environment. However, an accurate system is needed to make efficient use of this generated heat flux, that is usually wasted. Thermoelectric generators (TEGs) are solid-state gadgets utilized in the conversion of heat to electricity. Hence, the aim of this study is to convert the heat flux generated at the disc contact surface into electrical energy by employing a thermoelectric generator. Additionally, to store the harvested energy to power the battery which in turn charges the temperature monitoring systems. Thermoelectric generators were positioned at different geometrical points of the brake discs to achieve optimal efficiency and energy storage possibilities. A static model is

Fayzullayevich, Jamshid Valiev, Agyeman, Philip, Frimpong, Justice

DESIGN OF LOAD CELL OPERATED MAGNETIC BRAKING SYSTEM

2022-01-110603/29/2022

The traditional braking system uses hydraulic fluid with components such as master cylinder, floating calliper, brake pedal, and connecting rod. The disadvantage with this system is regular maintenance, changing of oil and leakage. To overcome these disadvantages and making it cost effective this work is proposing a Load-cell operated magnetic braking system. It is reliable and requires less maintenance. The braking process involves impressing load on the load cell installed upon the steering wheel of the car. The load is converted to electric signals and will be transferred to the amplifier, then this amplified signal is supplied to hub of the rotor which is magnetic operated and applies brake. This braking system has more safety and accuracy compared to traditional braking system. Brakes are disengaged magnetically and engaged electrically. This brake system is used for dynamic stopping and holding halt and has flexibility in controlling the braking force through voltage applied

Srivastava, Jay Prakash

Evaluating Simulation Driver Model Performance using Dynamometer Test Criteria

2022-01-063803/29/2022

The influence of driver modeling and drive cycle target speed trace modification on vehicle dynamics within energy consumption simulations is studied. EPA dynamometer speed error criteria and the SAE J2951 standard are applied to simulation outputs as proposed components of simulation validation, providing guidelines for acceptable vehicle speed outputs and allowing comparison of simulation results to reported EPA dynamometer test statistics. The combined effect of driver model tuning and drive cycle interpolation methods is investigated for the UDDS, HwFET and US06 drive cycles, with EPA-specified linearly interpolated speed trace and PI controller driver as a baseline result. Additional benefits of driver tuning are presented including a reduction in unnecessarily-aggressive simulated accelerator and brake pedal actuation, resulting in a 50% or greater drop in simulated vehicle RMS jerk and peak jerk in each analyzed case compared to baseline. For the simulated vehicle, a “lazy

Legg, Thomas, Nelson, Douglas

Investigation of Al2O3-Ni coated cast iron brake rotors under modified brake dynamometer test standards

2022-01-030903/29/2022

Due to the reduced or less-frequent usages of the friction brakes and the lower brake rotor temperature on electrical vehicles (EV), corrosion would much likely occur on brake rotors. Using hard braking to clean the corroded rotor surfaces often leads to extra rotor surface wear. Improvement in corrosion and wear resistance is an important technological topic to brake rotors for EVs. Many original equipment manufacturers (OEM) and their suppliers are exploring surface treatments including laser cladding and thermal spray processes on cast iron rotors to combat the corrosion issues. However, mentioned surface coating processes increase the cost of brake rotors and there is a need to search for cost-effective coating processes. In this research, a new Al2O3-Ni composite coating was proposed for preparation of a commercial cast iron brake rotor using both plasma electrolytic aluminating (PEA) and electroless nickel plating (ENP) processes. The added nickel was to fit in the intrinsic

Cai, Ran, Sun, Jiayi, Zhang, Jingzeng, Tjong, Jimi, Foots, Sean, Lavelle, Mark, Nie, Xueyuan

The Numerical Analysis of Brake Pad Related to The Properties of Composite Brake Pad Friction Material.

2022-01-036503/29/2022

This project outlines the effect of changing Young’s modulus, Poisson’s ratio, and shear modulus on the natural frequencies of brake pads. It aims to improve the understanding of the influence of friction material properties on the natural frequencies and observe how the natural frequency changes with the changes in the properties of the composite brake pad friction material. In addition, two different brake pad models (Pad-A and Pad-B) were designed using CATIA V5 software to study whether different pad aspect ratios can affect the influence of friction material properties on the natural frequencies. The finite element analysis (FEA) was utilized to derive the natural frequencies and mode shapes using ABAQUS software. In addition, an experimental modal analysis (EMA) was performed on Pad-A to evaluate the accuracy of the FEA. Furthermore, the factorial analysis was applied on the obtained natural frequencies for each pad to find out the material properties that have the main effect on

Ravanbod, Mohammad

External Automatic Slack Adjuster Performance Requirements

J1513_202111 (Current)

11/03/2021

The performance requirements have been established for external automatic slack adjusters when tested to SAE J1462.

Truck and Bus Foundation Brake Committee

Driveline Parking Brake Test Procedure for Medium Duty Vehicles

J2690_202110 (Current)

10/28/2021

This SAE Recommended Practice establishes uniform test procedures for friction based parking brake components used in conjunction with hydraulic service braked vehicles with a gross vehicle weight rating greater than 4500 kg (10 000 lb). The components covered in this document are the primary actuation and the foundation park brake. Various peripheral devices such as application dashboard switches or indicators are not included. These test procedures include the following: a Brake Related Tests 1 Brake Functional Performance 2 Brake Dynamic Torque Performance 3 Brake Corrosion Resistance 4 Brake Endurance with Torque 5 Brake Endurance without Torque 6 Vibration Resistance 7 Brake Ultimate Static Load 8 Brake Lining Wear Adjuster Function b Actuation Related Tests 1 Mechanical Actuator Functional Performance 2 Mechanical Actuator Endurance 3 Mechanical Actuator Quick Release 4 Mechanical Actuator Ultimate Load 5 Spring Apply Actuator Functional Performance 6 Spring Apply Actuator

Truck and Bus Hydraulic Brake Committee

Brake Lining Quality Test Procedure

J661_202110 (Current)

10/26/2021

The purpose of this SAE Recommended Practice is to establish a uniform laboratory procedure for securing and reporting the friction and wear characteristics of brake linings. The performance data obtained can be used for in-plant quality control by brake lining manufacturers and for the quality assessment of incoming shipments by the purchasers of brake linings.

Brake Linings Standards Committee