Review of automotive brake lining materials and their tribological properties

Brake lining material properties are considered an essential aspect of the safe operation of vehicles. The presented paper aims to present a comprehensive review of brake lining materials and their tribological properties including the proposed materials, their advantages and disadvantages, analysis of results, and test rig experiments. The first section of the paper includes brief information on brake lining materials, friction modifier additives, and recent developments in friction additives. The second section discusses the tribological performance of brake lining materials. Furthermore, the key mechanisms of the friction layer produced on the worn brake lining surface have been explained microscopically (HRTEM). Part of this review is devoted to demonstrating current research gaps and challenges related to brake performance in automotive for further research. In brief, this review study is highly significant, as it provides more detailed information regarding the performance of brake lining materials.

Thermal Analysis of Thermal Spray Coated Gray Cast Iron Brake Rotor

Braking is a process which transform the kinetic energy of the rotor into heat energy. During the braking phase, the frictional heat generated at the interface rotor–pad can lead to high temperatures (> 600 oC). In long-term frequent use of braking, increased temperature causes disc distortions, heat cracks, and causes degradation of the pad material. This creates a risk in the reduction of rotor-pad interface friction and loss of brake performance under safe driving conditions. In this study, the thermal monitoring of the thermal spray coated rotor was investigated and the variation of the friction coefficient and wear related thickness were measured. In addition, changes in torque forces at increasing temperatures were also evaluated.

Service-life prediction of newly-designed brake gears having in consideration innovation engineering concepts

Для получения максимальной эксплуатационной эффективности транспортно-технологических машин лесного комплекса решались вопросы рационального обоснования их конструктивных параметров и характеристик, а именно тормозных систем и их компонентов, что является основой безопасной эксплуатации и максимальной производственной отдачи рассматриваемой техники. Приведено обобщение результатов экспериментальных исследований в направлении повышения эффективности тормозных систем транспортно-технологических машин для последующего прогнозирования ресурса вновь проектируемых тормозных механизмов с учетом инновационных инженерных решений на уровне изобретения. В изобретении «Способ циркуляции воздуха при подаче его под давлением на фрикционные поверхности тормозного механизма в процессе торможения и устройство для его осуществления» предлагается в процессе торможения обеспечить такую циркуляцию воздуха в тормозном механизме колеса, что при сближении колодки и барабана реализуется его подача под давлением на фрикционные поверхности тормозного механизма. Для реализации такого технического решения проводились комплексные экспериментальные исследования с целью выявления предполагаемых возможных положительных эффектов. Выполнен анализ результатов экспериментальных исследований, который наглядно показывает повышение тормозной эффективности лесотранспортных машин. Для решения обобщающей задачи, связанной с повышением тормозной эффективности лесотранспортных машин, предлагается эвристический подход. В качестве рабочей гипотезы имеет место первая теорема подобия. Принятые во внимание представленные ранее предположения о подобии процессов тормозных колодочных механизмов экспериментального стенда и некоторого виртуального погрузчика позволил прогнозировать ресурс тормозного механизма и при реализации приведенного технического решения. В результате представлена методика прогнозирования ресурса вновь проектируемых тормозных механизмов с учетом инновационных инженерных решений на уровне изобретения. Specific rational problems were brought to consideration in order to validate design parameters and characteristics, particularly behavior of brake systems and their components, for gaining maximum performance of forestry vehicles, thereby providing safe operation and maximum output efficiency of the machinery concerned. The experimental study results have been generalized to improve efficiency of transport-processing vehicle brake systems for predicting service life of newly designed brake gears having in consideration innovation engineering concepts subject to the invention. According to the invention “Method of compressed air circulation with air fed to the brake gear friction surfaces during braking and its embodiment”, it is offered to provide air circulation in the wheel brake gear during braking so that air is charged to the brake gear friction surfaces with a brake gear block and drum moving close to each other. Some complex experimental studies were held in order to identify possible positive effects for implementing such technical decision. The experimental study results were analyzed for demonstrating improvement of forestry vehicle brake performance. The heuristic approach was offered for solving the problem generalized in order to improve forestry vehicle brake performance. The first similarity theorem was applied as a working hypothesis. Taking into account the previously offered theories of similarity of brake block behavior when testing on a bench and on a virtual loader, it was possible to predict service life of the brake gear subject to the above technical decision. As a result, the method of service life prediction of newly-designed brake gears having in consideration innovation engineering concepts subject to the invention was provided.

Optimization of temperature measurement on the bus drum brake as a basis for developing brake fault signals

Brake failure is always possible due to several factors that are difficult to control, such as a slight leak in the brake hose due to an impact or a rat bite. In the latest research, the development of a brake performance detection tool has been started, but how to detect a brake temperature more efficiently on the brakes of large vehicles has not been specified. Given the significant impact of losses due to brake failure and accidents that are still occurring, this research plays an important role. It must be completed immediately so that accident cases can be reduced. The object of this research is where the position of the maximum brake temperature occurs? How to measure brake temperature is more practical? What sensor is optimal in detecting a brake temperature? The research method is carried out in a systematic stage that ends with an experimental method. This study indicates that the maximum temperature is relative to the entire friction area between the canvas and the drum brake. The most efficient sensor placement is in the hole in the drum brake cover so that installation is more practical and the brakes are not disturbed by the sensor’s presence. The optimal sensor is a thermocouple sensor because it is more stable to vibrations and more resistant to mud disturbances than infrared sensors. When using a thermocouple sensor, the temperature detection results must be corrected. The correction factor can be made with the equation y=10.3670+1.3205x–0.0003x2, where y is the actual temperature displayed, and x is the input temperature from the thermocouple sensor’s initial detection. Accurate brake temperature detection results will be developed as a signal for detecting brake faults in real-time to avoid brake failure. Finally, the safety of public transportation can be improved

A new prototype system for automated suppression of disc brake squeal

This paper presents a new prototype system capable of automated disc brake squeal suppression using a method of varying the leading and trailing piston pressures in a multi-piston opposed brake caliper. The new system consists of a novel modular four-piston brake caliper, a two-channel brake actuation system and an advanced control system that is capable of varying the leading/trailing pressure ratio (LTPR) when squeal is detected. The amended LTPR results in movement of the centre of pressure (CoP) position at the pad/disc interface, which leads to new dynamic parameters of the brake system and thereby to different squeal propensity. Moreover, the control system maintains the overall brake torque at a constant value, so the variation of the LTPR on the brake performance is minimised. Experiments using the current disc brake setup showed that by varying the LTPR, thereby changing the CoP position, the squeal occurrence can be successfully controlled. Large leading or trailing offsets typically lead to a quieter brake. Tests demonstrating operation of the proposed squeal control system in an automatic mode reduced the squeal occurrence significantly for a given duty cycle.

Braking-Style-Based Optimization for Regenerative Braking System of an Electric Commercial Vehicle

With the development of intelligent transportation system, intelligent network technology has been studied on a large scale in vehicle field. Electrification of vehicles and drive-by-wire chassis provide possibilities for the application of connected autonomous electrified vehicles. Regenerative braking control is an important field among drive-by-wire chassis control technologies. Regenerative braking control is a multi-objective optimization problem, which has the aim of improving regenerative energy efficiency, brake performance, and brake comfort. Therefore, a model predictive control (MPC) is proposed to solve the problem with consideration of different brake styles, such as aggressive, moderate and conservative. Then, the models of the main components associated with the regenerative braking system are designed and built up in a typical deceleration process for simulation and analysis. The simulation results show that the aggressive style mode is the best brake performance, which cause issues on brake comfort as well. The conservative style mode makes full use of motor braking and has advantage of the brake comfort and regenerative energy efficiency. But, it is not good at rapid braking performance of low brake intensity. The moderate style mode is suitable for most drivers, which is balanced of the above characteristics. Finally, experimental tests under ECE driving cycle are also carried out to further verify the characteristics of proposed three brake modes.