Browse Topic: Brake torque

Items (255)

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

Increasing the Effective AKI of Fuels Using Port Water Injection (Part II)

2022-01-052303/29/2022

This is part II of the paper on ‘Increasing the Effective AKI of Fuels Using Port Water Injection’ In the United States, the metric used to quantify the anti-knock performance of fuels is Anti Knock Index (AKI), which is the average of Research Octane Number (RON) and Motor Octane Number (MON). Fuels with higher AKI are expected to have a better knock mitigating properties, which enables the engine to be run closer to Maximum Brake Torque (MBT) spark timing in the knock limited region. The work done in part I of the study quantified the amount of water required (as a ratio with fuel and absolute) to increase the performance of low AKI fuels in order to match their performance to that of a higher AKI reference fuel, thus increasing their ‘effective AKI’. This paper builds upon the work done in part I of the study by repeating a part of the test matrix with Primary Reference Fuels (PRFs), with iso-octane (PRF100) as the reference fuel and lower PRFs used to match its performance with the

Gopujkar, Siddharth, Worm, Jeremy, Barros, Sam, Bonfochi Vinhaes, Vinicius, Hansley, William

Systems of automatic brake torque reduction on the wheels of one axle of the car

2021-01-126610/11/2021

Braking mechanisms are the most unstable elements of a vehicle's braking system. Instability of braking torques on the wheels of one axle of the vehicle leads to the appearance of the braking forces unevenness, and then- to the vehicle skidding during braking. At one time, the appearance of open-type disc brakes made it possible to reduce the unevenness of the braking forces on the sides of the car due to their higher characteristics of energy intensity and stability. However, the lack of feedback between the left and right disc brakes mounted on the same axle of the vehicle does not allow reducing the unevenness of the braking forces to an acceptable minimum. The authors of the work studied and proposed several systems for automatic reduction of the braking torques unevenness for braking mechanisms mounted on the wheels of one axle. The following options are proposed: - hydrostatic system for automatic reduction of braking torques unevenness on the wheels of the car front axle

Podrigalo, Mikhail, Kholodov, Mykhailo, Stepanov, Victor, Soloviov, Oleh, Aleksandrov, Yevgeniy, Volontsevych, Dmytro, Morozov, Oleksandr

Braking Systems for High Performance Electric Vehicles - A Design Study

2020-01-161210/05/2020

Any young person who has taken delight in playing with toy slot cars knows that the world of racing and the world of electric cars has been intertwined for a long time. And anyone who has driven a modern performance electric vehicle knows that the instant acceleration, exhilarating speeds, and joy of driving of slot cars is reflected in these full sized “toys”, with the many more practical benefits that come from being full-sized and steerable. There is strong foreshadowing of a vibrant future for performance cars in some of the EV’s on the market now and in the near future, some offering “ludicrous” acceleration, and others storied nameplates with performance to match. The ease at which powerful electric drives can capably hurtle a massive vehicle around the track at high speeds, combined with the potential for the same electric drives to exert powerful regenerative braking, creates a very interesting situation for brake engineers. What wins out in the end - raw power or regenerative

Antanaitis, David, Robere, Matthew

Air Brake Performance and Wear Test Code Commercial Vehicle Inertia Dynamometer

J2115_202008 (Current)

08/20/2020

This SAE Standard provides test procedures for air and air-over-hydraulic disc or drum brakes used for on-highway commercial vehicles over 4536 kg (10000 pounds) GVWR. This recommended practice includes the pass/fail criteria of Federal Motor Vehicle Safety Standard No. TP-121D-01.

Truck and Bus Foundation Brake Committee

Air Brake Performance and Wear Test Code Commercial Vehicle Inertia Dynamometer

J2115_202008-TEST-REC (Historical)08/20/2020

This SAE Standard provides test procedures for air and air-over-hydraulic disc or drum brakes used for on-highway commercial vehicles over 4536 kg (10000 pounds) GVWR. This recommended practice includes the pass/fail criteria of Federal Motor Vehicle Safety Standard No. TP-121D-01.

Truck and Bus Foundation Brake Committee

Integrated Regenerative Braking System and Anti-Lock Braking System for Hybrid Electric Vehicles & Battery Electric Vehicles

2020-01-084604/14/2020

This paper describes development of an integrated regenerative braking system and anti-lock brake system (ABS) control during an ABS event for hybrid and electric vehicles with drivelines containing a single electric motor connected to the axle shaft through an open differential. The control objectives are to recuperate the maximum amount of kinetic energy during an ABS event, and to provide no degraded anti-lock control behavior as seen in vehicles with regenerative braking disabled. The paper first presents a detailed control system analysis to reveal the inherent property of non-zero regenerative braking torque control during ABS event and explain the reason why regenerative braking torque can increase the wheel slip during ABS event with existing regenerative braking control strategies. Then, the regenerative brake control problem during ABS events is formulated with a unified control system architecture where the regenerative braking torque is coordinated with the friction braking

Yao, Yixin, Zhao, Yanan, Yamazaki, Mark

Effect of Stator Surface Area on Braking Torque and Wall Heat Dissipation of Magnetorheological Fluid Retarder

2020-01-093704/14/2020

Magnetorheological fluid (MRF) is used as the transmission medium of the hydraulic retarder. The rheological properties are regulated by changing the magnetic field to achieve accurate control of the retarder's braking torque. Under the action of the external magnetic field, the flow structure and performance of the MRF retarder will be changed in a short time. The apparent viscosity coefficient increases by several orders of magnitude, the fluidity deteriorates and the heat generated by the brake cannot be transferred through the liquid circulation, which will affect the braking torque of the retarder. Changing the surface area of the stator also has an influence on the braking torque of the retarder and the wall heat dissipation. In this study, the relationship between the braking torque of the MRF retarder and the stator surface area of the retarder was analyzed. In addition, phase change materials were used to directly dissipate heat on the retarder surface to improve the heat

Liu, ZhiQiang, Tan, Gangfeng, Tian, Zhongpeng, Zhou, Mi, Agyeman, Philip, Frimpong, Justice

Development challenges of hydraulic brakes for commercial vehicles

2019-36-001301/13/2020

The automotive research and development environment is increasingly challenging and complex, full of new technologies, regulations and customized customer needs. In addition, the cargo transportation market is very dynamic and competitive, becoming complex the strategies for companies in this segment. According to Anfavea (2018), this trend, especially in large urban centers, has driven the intention to use light commercial vehicles to capillize deliveries in destinations with a high demographic concentration and traffic limited to medium and heavy vehicles. In this scenario, the demand for diversified products is increasing in order to overcome the main tradeoff: “minimizing the size of the trucks and maximize the load capacity”. It brings the number of complex projects. The brake system is greatly impacted in these developments mainly because light commercial vehicles are situated in a weight range that we can call "identity crisis" if on the one hand they need an upgrade compared to

Vetter, Narã Vieira, Carlos de Oliveira, Antonio, Fontes, Eduardo Henrique Souza, Nogueira, Felipe, Fonseca, Guilherme Henrique, Nuss de Souza, Luis Fernando, Oliveira dos Reis, Rodrigo de, Manenti, Vangelo Cardoso

Analysis of Active Collision Avoidance Performance Based on Cooperative Regenerative Auxiliary Braking System

2019-01-502711/04/2019

Active collision avoidance can assist drivers to avoid longitudinal collision through active brake. Regenerative braking can improve the driving range and braking response speed. At this stage, conventional hydraulic braking system limits the implements of above technologies because of its poor performance of response speed and coordinated control. While the brake-by-wire system is a better actuator that can fulfill requirements of automotive electric and intelligent development due to its rapid response and flexible adjustment. However, the system control algorithm becomes more complicated with introduction of regenerative braking and active collision avoidance function, which is also the main problem solved in this paper. First, a new type of cooperative regenerative auxiliary braking system (CRABS) of intelligent electric vehicles, which integrates the functions of brake-by-wire, regenerative braking and active collision avoidance, is proposed, for purpose of analyzing the

Hou, Xiaohui, Zhang, Junzhi, Zhang, Zhongshi, He, Chengkun

Information on Brake-By-Wire (BBW) Brake Control Systems

AIR5372A (Current)10/25/2019

This SAE Aerospace Information Report (AIR) describes the design approaches used for current applications of aircraft Brake-by-Wire (BBW) control systems. The document also discusses the experience gained during service, and covers system, ergonomic, hardware, and development aspects. The document includes the lessons that have been learned during application of the technology. Although there are a variety of approaches that have been used in the design of BBW systems, the main focus of this document is on the current state of the art systems.

A-5A Wheels, Brakes and Skid Controls Committee

Brake Rotor Corrosion and Friction Cleaning Effect on Vehicle Judder Performance

2019-01-211509/15/2019

Brake disc corrosion has emerged as an important field of study within the automotive industry due to the wide range of lining materials that are currently used worldwide, and their inherent rust-cleaning properties. The presence of oxide layers irregularly deposited on the cast iron disc surfaces usually leads to a forced, braking-induced vibration that can reach the driver’s position as a pronounced annoyance. Hence, the friction material composition directly impacts on the judder performance during the early corrosion-removal stage. This study incorporates both dynamometer and vehicle tests into the definition of a predictive methodology that allows corrosion-induced vibrations to be investigated at both system and vehicle levels. The oxide film is artificially generated by means of a salt spray chamber under steady-state climate conditions in order to guarantee a repetitive and robust procedure. The vibration response of the system is objectively evaluated in the form of caliper

Molina Montasell, Narcís, Ferrer, Bernat

The Improvement Brake’s Qualities of Vehicle by Developing the Method of the Choosing Frictional Pairs of the Brakes Mechanisms

2019-01-214509/15/2019

One of the reasons for the large number of road accidents on highways in Ukraine [1] is the instability of the braking properties due to the unstable characteristics of the brake mechanisms’ friction pairs. The manufacturer produces new automobiles with installed brake pairs (brake pads and their counter bodies), which have passed long-term tests for the stability of the friction coefficient and braking forces distribution of between the axles. This ensures the compatibility of the friction pairs characteristics for front and rear brake mechanisms according to the criteria of heat resistance. During operation, instead of worn-out brake pads, brake discs and drums, drivers can purchase new ones, manufactured as spare parts. However, in the well-known literature there are no methods that allow to check the compatibility of the friction pairs characteristics for front and rear brake mechanisms according to the criteria of heat resistance. In the article a method for choosing a set of

Podrigalo, Mikhail, Klets, Dmytro, Kholodov, Mykhailo, Bogomolov, Viktor, Turenko, Anatoliy, Molodan, Andrii, Rudzinskyi, Volodymyr, Tarasov, Yurii, Mykolai, Aloksa, Hatsko, Vasyl

Brake Block Effectiveness Rating

J1802_201906 (Current)06/06/2019

This SAE Recommended Practice provides the test procedure and methods to calculate the effectiveness of brake blocks, using an inertia dynamometer. To minimize testing variability, and to optimize standardization and correlation, a single, high volume size of brake block is specified (FMSI No. 4515E) and evaluated in a reference S-cam brake assembly of 419 mm x 178 mm (16.5 in x 7.0 in) size, using a specified brake drum.

Truck and Bus Foundation Brake Committee

Development of Parametrically Integrated Software Platform for Passenger Car Brake System

2019-01-123104/02/2019

The hydraulic servo brake system for passenger car plays a central role in occupant protection, which directly affects the automotive active safety and road handling. In this paper, an integrated parameterized software platform of hydraulic servo brake systems is proposed to realize fast and efficient braking system development. At first, according to the structure and working principle of the hydraulic servo brake system, the relationship among amount of fluid required for brake caliper, pedal feel and performance of the brake system is analyzed. Then, based on kinematics and dynamics of the hydraulic servo brake system, a simulation model for analyze pedal feel and amount of fluid required for brake caliper is built in AMESim, which is composed of brake pedal, vacuum booster, brake master cylinder, brake hoses and brake calipers, etc. In addition, the accuracy of the simulation model is verified by bench tests, and the significantly influential factors on the amount of fluid required

Pan, Jin, Guo, Xuexun, Zhou, Wei, Pei, Xiaofei, Pan, Hao, Zhang, Jie

A New Model Describing the Formation of Heat Cracks in Brake Discs for Commercial Vehicles

2018-01-188210/05/2018

During the development process of brake discs for commercial vehicles, heat cracks are a frequent problem. Since no profound model to forecast the occurrence of cracks has been presented yet, their prediction is hardly ever possible. The standardized heat crack test puts the brake disc under severe thermomechanical load and therefore forces it into cracking. In this paper, results from a series of heat crack tests on the dynamometer are presented, which provide insight into the hidden processes that accelerate or slow down the heat crack propagation in brake discs. This includes an extensive experimental setup using a thermographic camera, a set of capacitive displacement sensors, a pyrometer, and sliding thermocouples as well as a unique eddy-current heat crack detector that was developed at TU Darmstadt. Continuous monitoring of disc deformation, surface temperature, and crack propagation at high sampling rates provides the base for a new, profound causal model. The model describes a

Bilgic Istoc, Sami, Winner, Hermann

Performance Evaluation of Two Wheeler Brake System Using Coupled Thermo-Mechanical Simulation

2018-01-189610/05/2018

Safety aspect has been a key requirement in designing braking system. However, non-safety aspect like NVH and thermal performance are gaining equal importance. High engine capacity (cc) motorcycles are prone to thermal and NVH issues as braking energies are more. Therefore, virtual validation of brake disc system by considering both dynamic and thermal load with predefined assumptions is a toughest challenge when confronted with reality boundary conditions. Thus, the paper comes in a unique way of coupling dynamic and thermal load executed between multi body dynamics (MBD) and heat transfer equation which will convey results closer to real time scenario. MBD solves motion and the dynamic influence on heat transfer is calculated using “sliding boundary condition”. A series of repeated braking condition are performed on front brake disc of motorcycle. The results obtained from the analysis shows critical temperature rise. As a consequence, disc thickness variation (DTV) due to thermal

Sukumaran, Suraj, Kalani, Dinesh, Suryavanshi, Yogesh, Kokane, Girish, Deshpande, Moresh, Kharul, Ravindra

Properties and Limitation of an Oxide Coated Aluminum Brake Rotor

2018-01-187710/05/2018

The electrification of the powertrain and the thereto related recuperation of the electric engine saves the energy in the battery and thus reduces the thermally dissipated brake energy, which leads to lower brake rotor temperatures compared to combustion engine vehicles (ICEVs). These new conditions enable to reconsider brake disc concepts. Including lightweight design in heavy battery electric vehicles (BEVs) and the increasingly reliant corrosion resistance of brake rotors, Aluminum is a promising approach for new brake disc concepts. In the past, Aluminum brake disc concepts have already been deployed. For instance Aluminum Metal-Matrix Composite (Al-MMC) concepts in the Lotus Elise S1 and on the rear axle of the Volvo V40 [1]. The presented concept is a different approach and separates the friction system from the bulk Aluminum brake disc, achieved by coating of the friction rings. By locally reinforcing the friction rings, the good machinability and ductility of the base body is

Gulden, Florian, Gramstat, Sebastian, Stich, Anton, Hoppel, Heinz Werner, Tetzlaff, Ulrich

Inertia Calculation for Single-Ended Inertia-Dynamometer Testing

J2789_201809 (Historical)09/26/2018

This procedure provides methods to determine the appropriate inertia values for all passenger cars and light trucks up to 4540 kg of GVWR. For the same vehicle application and axle (front or rear), different tests sections or brake applications may use different inertia values to reflect the duty-cycle and loading conditions indicated on the specific test.

Brake Dynamometer Standards Committee

Experimental Investigation of Low-Frequency Vibration Patterns in Automotive Disk Brake Systems: Utilization Study for Modal Simulation Methods

2018-01-151306/13/2018

Increasing demands on automotive comfort as well as diminishing vehicle noise levels draw new attention towards low-frequency vibration and noise issues of disk brake systems such as creep groan and moan. In view of this problem, the experimental investigation of relevant phenomena is within the scope of this article. The related experiments concerning two different setups have been performed at a drum driven suspension and brake test rig. Both assemblies consisted of a front axle corner including all parts of the integrated brake system. In order to gain understanding of characteristic triggering mechanisms and fundamental subsystem interactions, and moreover, to verify the suitability of modal methods for simulative evaluations of creep groan or moan, specifically elaborated Operating Deflection Shape (ODS) techniques have been applied. Via analyses of four different creep groan emergences, global stick-slip cycles between disk and pads are revealed. For two dissimilar vibrations in

Pürscher, Manuel, Huemer-Kals, Severin, Fischer, Peter

A Braking Force Distribution Strategy in Integrated Braking System Based on Wear Control and Hitch Force Control

2018-01-082704/03/2018

A braking force distribution strategy in integrated braking system composed of the main braking system and the auxiliary braking system based on braking pad wear control and hitch force control under non-emergency braking condition is proposed based on the Electronically Controlled Braking System (EBS) to reduce the difference in braking pad wear between different axles and to decrease hitch force between tractors and trailers. The proposed strategy distributes the braking force based on the desired braking intensity, the degree of the braking pad wear and the limits of certain braking regulations to solve the coupling problems between braking safety, economical efficiency of braking and the comfort of drivers. Computer co-simulations of the proposed strategy are performed. The braking force distribution strategy is verified under condition of equal wear of braking pad, condition of greater wear on the front axle of tractor and condition of greater wear on the rear axle of the tractor

Zheng, Hongyu, Liu, Chen, Wang, Linlin

Development of a 12-NodeThermodynamic Simulation Model of a Disc Brake Assembly

2018-01-053404/03/2018

Overheated brakes on a heavy truck can lead to a loss of braking and subsequent crash. This typically occurs after prolonged braking on a downhill grade. The problem is often accompanied by improper brake adjustment, causing one or more of the actuators to reach the end of travel due to thermal expansion. Reconstruction of this type of crash requires the consideration of overheated wheel brake assemblies. A thermodynamic model of a drum-type foundation brake is included in the HVE simulation environment and has been used successfully to study this phenomenon. However, newer on-highway trucks are often fitted with disc brakes. A similar thermodynamic model for a heavy truck disc brake does not exist, making the problem described above difficult to address. This paper describes a new thermodynamic model of a disc foundation brake, such as those often fitted on newer heavy trucks. The model is based on classic thermodynamic heat transfer principles that describe the rate of heat flow

Truck Brake Failure: Differences between Failure Modes for Drum and Disc Brakes

2018-01-052804/03/2018

On-highway heavy trucks are fitted with air disc brakes with increasing frequency. Disc brakes and traditional air drum brakes have different adjustment and heat dissipation characteristics. These differences lead to different failure modes when overheated. This paper describes how adjustment and other in-use factors affect the general braking capability of on-highway trucks fitted with disc and drum brakes. Simulations of a loaded tractor-trailer on a long, down-hill grade are used to predict brake temperature increase over time, and how that temperature increase can result in a runaway condition. The tractor and trailer are modeled with both traditional drum brakes and new disc brakes to illustrate operational differences between the two brake types.

Choosing the Right Brake for Robotic Applications

TBMG-2881204/01/2018

Industrial robots play an essential role in manufacturing, from assembly, to pick-and-place, to packaging. One of the major risks of robotics — and what OEMs seek to mitigate — is uncontrolled or non-commanded motion by a robot. Most electric robots today incorporate servomotors for direct-drive operation. This approach largely eliminates the need for clutches, but robots still need brakes, both to apply holding torque once the motor moving the joint has stopped, and to provide dynamic stopping in the event of emergency.

Automotive Brake Noise and Vibration Standard Nomenclature

J2786_201712 (Current)12/20/2017

This document defines various vehicular noises and vibrations that are attributed to being created by the foundation brake components of the vehicle, particularly on passenger cars and light trucks. These definitions cover both disc and drum brakes. The frequency ranges from near zero Hz (tactile sensations) all the way up to 17 kHz, or the upper limit of normal hearing. These noises and vibrations may either directly radiate off the brake system or provide the excitation energy that causes other vehicle components to react.

Brake NVH Standards Committee

Sizing Next Generation High Performance Brake Systems with Copper Free Linings

2017-01-253209/17/2017

The high performance brake systems of today are usually in a delicate balance - walking the fine line between being overpowered by some of the most potent powertrains, some of the grippiest tires, and some of the most demanding race tracks that the automotive world has ever seen - and saddling the vehicle with excess kilograms of unsprung mass with oversized brakes, forcing significant compromises in drivability with oversized tires and wheels. Brake system design for high performance vehicles has often relied on a very deep understanding of friction material performance (friction, wear, and compressibility) in race track conditions, with sufficient knowledge to enable this razor’s edge design. With significant restrictions in copper content of automotive brake linings becoming reality in California and Washington State in 2021, and a more or less complete phase-out of copper in linings occurring in 2024, one of the key ingredients of high performance linings - critical for heat

Antanaitis, David B., Shenberger, Michael, Votteler, Max

Combined Hill Descent Braking Strategy for Heavy Truck in the Featured-Slope

2017-01-253509/17/2017

The continuous braking for the brake drum will cause the brake thermal decay when the heavy truck is driving down the long slope in the mountain areas. It reduces the heavy truck’s braking performance and the braking safety. The engine braking and the hydraulic retarder braking both consume the kinetic energy of the heavy truck and can assist the truck driving in the mountain areas. This research proposes a combined hill descent braking strategy for heavy truck based on the recorded information of the slopes to ensure the braking safety of the heavy truck. The vehicle dynamic model and the brake drum temperature rising model are established to analyze the drum’s temperature variation during the downhill progress of the heavy truck. Then based on the slope information, the combined braking temperature variation is analyzed considering the characteristics of the engine braking, the drum braking and the hydraulic retarder braking. The research result shows that the brake drum’s

Xu, Yongbing, Mei, Binyu, Xiao, Longjie, XIA, Wanyang, Tan, Gangfeng

A Comparison of Braking Behavior between an IC Engine and Pure Electric Vehicle in Los Angeles City Driving Conditions

2017-01-251809/17/2017

The Los Angeles City Traffic Brake Test Schedule has been an established procedure used almost universally for generations by vehicle manufacturers to evaluate and validate braking systems for the attributes of NVH and brake wear behavior. The Los Angeles driving route, commonly known as the Los Angeles City Traffic Test (LACT), has long been considered an effective and “quasi” extreme set of real world driving conditions representative of the US passenger vehicle market and have been covered in other analysis including SAE Technical Paper 2002-01-2600 [1] The performance of a vehicle, relative to braking, in LACT conditions is typically influenced by basic vehicle and brake system attributes including the ratios of vehicle mass to brake sizing attributes, friction material selection, and the acceleration, drag, and cooling behavior of the vehicle. The general character of the LACT Route and typical driving behavior establishes an energy input to the braking system that must be managed

Hall, Thomas J.

Influences of Initial DTV on Thermomechnical Coupling in Disc Brake System

2017-01-249209/17/2017

In this paper, the initial disc thickness variation (DTV) of a ventilated disc in automotive brake system is modeled as sinusoidal function of the second order. The transient thermomechanical coupling properties of the brake system is simulated using finite element (FE) modeling. The system models and results were verified by a thermomechanical coupling test of a disc brake conducted on a brake dynamometer. By using varied evaluation indexes such as the temperature distribution, the normal stress and the elastic deformation of disc surfaces, the influences of the initial DTV and its direction as well as its amplitude on the thermomechanical coupling characteristics were analyzed. The simulation results show that the distribution of temperature and the normal stress in circumferential direction exhibit the same sinusoidal function of the second order as the modeled initial DTV property, which is different from the thermomechanical coupling characteristics caused by disc surface initial

Meng, Dejian, Wang, Ziyi, Zhang, Lijun, Yu, Zhuoping

Brake System Performance at Higher Mileage

2017-01-250209/17/2017

The purchase of a new automobile is unquestionably a significant investment for most customers, and with this recognition, comes a correspondingly significant expectation for quality and reliability. Amongst automotive systems -when it comes to considerations of reliability - the brakes (perhaps along with the tires) occupy a rarified position of being located in a harsh environment, subjected to continuous wear throughout their use, and are critical to the safe performance of the vehicle. Maintenance of the brake system is therefore a fact of life for most drivers - something that almost everyone must do, yet given the potentially considerable expense, it is something that of great benefit to minimize. Additionally, the performance of the brake system (like the tires) can change over the useful life of the components, realized in the form of changing friction levels, fluid consumption, and drag at a brake corner level, and realized to the driver in the form of changing pedal effort

Antanaitis, David B., Robere, Matthew

Estimation of Brake Friction Coefficient for Blending Function of Base Braking Control

2017-01-252009/17/2017

The brake architecture of hybrid and full electric vehicle includes the distinctive function of brake blending. Known approaches draw upon the maximum energy recuperation strategy and neglect the operation mode of friction brakes. Within this framework, an efficient control of the blending functions is demanded to compensate external disturbances induced by unpredictable variations of the pad disc friction coefficient. In addition, the control demand distribution between the conventional frictional brake system and the electric motors can incur failures that compromise the frictional braking performance and safety. However, deviation of friction coefficient value given in controller from actual one can induce undesirable deterioration of brake control functions. The main objective of the presented study is to propose a method to compensate disturbances induced by variations of brake linings friction coefficient through modifications of the brake torque demand for the enhancement of

Ricciardi, Vincenzo, Savitski, Dzmitry, Augsburg, Klaus, Ivanov, Valentin

Methodology of Automatic Slack Brake Adjuster Definition Considering Foundation Brake System Characteristics

2017-36-000405/24/2017

S-cam brakes concept are largely used by commercial vehicles around the world due to its low cost, easy maintenance and robustness. An important component of s-cam brakes is the slack adjuster, that is responsible for amplify brake chamber forces and assure correct lining and drum clearance. Therefore usually slack adjuster mechanism characteristics are defined only by empiric method considering trial and error tentative. This paper aims to demonstrate a methodology created to develop new air s-cam brakes slack adjuster definition taken in consideration its interface with other brake components. During this study was identified design specification for each component and its influence on adjustment process. It was verified the intrinsic characteristics of slack adjuster mechanism and developed a calculation tool to predict its actuation on the brake. The interface of slack adjuster with other foundation brake components and drum compliance were also studied. In order to validate the

Prado, Wesley Bolognesi, Iombriller, Silvia Faria, Chiu, Jonathan Orsi, Roman, Alexandre

Yaw Stability Enhancement of Articulated Commercial Vehicles via Gain-Scheduling Optimal Control Approach

2017-01-043703/28/2017

In this paper, a gain-scheduling optimal control approach is proposed to enhance yaw stability of articulated commercial vehicles through active braking of the proper wheel(s). For this purpose, an optimal feedback control is used to design a family of yaw moment controllers considering a broad range of vehicle velocities. The yaw moment controller is designed such that the instantaneous tractor yaw rate and articulation angle responses are forced to track the target values at each specific vehicle velocity. A gain scheduling mechanism is subsequently constructed via interpolations among the controllers. Furthermore, yaw moments derived from the proposed controller are realized by braking torque distribution among the appropriate wheels. The effectiveness of the proposed yaw stability control scheme is evaluated through software-in-the-loop (SIL) co-simulations involving Matlab/Simulink and TruckSim under lane change maneuvers. Simulation results demonstrate that the proposed gain

Li, Bin, Rakheja, Subhash

Use of Electric Driveline for a Cooperative Braking Strategy

2017-01-159503/28/2017

This paper presents a brake control strategy with a novel approach to the allocation of actuator effort in an electric vehicle. The proposed strategy relies on a combination of the conventional hydraulic braking system and the electric machine in order to improve braking performance. The higher response frequency of the electric machine is paired with the additional braking torque employed by the hydraulic brakes using an integrated control allocation strategy, which allows for a constant availability of a faster and more accurate modulation of both wheel torque and wheel speed. Therefore, the availability of an electric machine as a fast longitudinal actuator yields to an improved tracking of the desired wheel slip, especially when compared to the hydraulic actuators used in traditional braking applications. As a result, this strategy leads to a clear and considerable reduction of the braking distance, removes the need for a hydraulic modulator and thereby also removes the disturbing

Arat, Mustafa Ali, Duringhof, Hans-Martin, Hagnander, Johan, L. Simoes, Eduardo

Conversion of Drum Brake System to Disc Brake with CAE and CFD: Resulted in Optimized Brake Rotor Design and Improved Performance

2017-26-026101/10/2017

Paper explains conversion of existing drum brake system to disc brake system with complete digital validation at structural as well as thermal level to make sure First Time Right Design before physical part development. To provide leverage to quick design, modification and selection of brake system according to vehicle configuration, a virtual computational fluid dynamics (CFD) simulation process is developed and validated with test results. Temperature variation over brake drum and disc in internal standard braking cycle is measured virtually and correlated with test results. Also Fade testing criteria’s were considered during CFD analysis. This up gradation is must considering technology enhancement trend and safety in automotive segment. In current competitive market scenario and as per customer requirements, front disc brake module is becoming necessary not only for passenger segment but also for commercial segment vehicle. Brake system design is challenging task as it deals with

Anil Shah, Ashesh, Patidar, Ashok

Interactive Effects of Thermal Deformation and Wear on Lateral Runout and Thickness Variation of Brake Disc Rotors

2016-01-193909/18/2016

Brake judder is one of the most serious problems in automotive-brake systems. It is basically a forced vibration caused by the friction-surface geometry of a brake disc, and therefore, disc rotors play a significant role in judder. There are two types of judder: cold and hot. Hot judder is caused by the thermo-mechanical deformation of a brake disc due to high-speed braking. There are several shapes of deformation, e.g., coning and circumferential waviness. Circumferential waviness is caused by thermo-mechanical buckling and typically found as a butterfly shape in a 2nd rotational-order and hot-spotting. In a previous paper, two groups of disc castings with different material homogeneity were machined intentionally to have two kinds of dimensional variations. From repetitive high-speed braking tests of these discs, both the material and dimensional homogeneity were found to affect the wave-like deformation of discs in the 1st and 2nd rotational-orders with different significance

Okamura, Toshikazu

Novel Disc Brake System Leading towards Payload Increment and Maintenance Improvement

2016-01-193609/18/2016

Brake system for any vehicle plays an important role, as safety comes at highest level, also domestic and international safety norms for commercial vehicles are getting stringent. In current scenario of highly competitive commercial market, Payload advantage comes at peak level in customer demand list, also maintainability plays an important role to make sure least vehicle downtime, linked to customer profitability. Finally, if product has less complexity (reducing no. of parts), then it will provide add on benefit to any organization. Considering these customer oriented perspectives, mainly payload & maintenance, along with regulation compliance. We have proposed new Disc brake system for heavy duty commercial vehicle providing maximum payload benefit, along with enhancement in maintainability. It has also enhanced performance and meeting all legislative criteria at vehicle level.

Anil Shah, Ashesh, Raj, Kshitiz

Alkali-Activated Inorganic Based Brake Pads: Realization and Performances of Alternative Friction Materials for a Concrete Industrial Application

2016-01-191309/18/2016

Organic brake pads for automotive can be defined as brake linings with bonding matrix constituted of high-temperature thermosetting resins. Bonded together inside the polymeric binder are a mix of components (e.g. abrasives, lubricants, reinforcements, fillers, modifiers…), each playing a distinctive role in determining the tribology and friction activity of the final friction material. The herein reported work presents inorganic “alkali-activated”-based materials suitable for the production of alternative brake linings (i.e. brake pads), by means of an unconventional low-temperature wet process. Exploiting the hydraulic activity of specific components when exposed to an alkaline environment, such peculiar inorganic materials are capable of coming to a complete hardening without the need of traditional high-temperature energivorous procedures. The main advantages of these materials resides in: the decreased embodied energy of the employed raw materials, the reduction of process costs

Sanguineti, Alessandro, Tosi, Federico, Bonfanti, Andrea, Rampinelli, Flavio

Compilation of Freezing Brake Experience and Potential Designs and Operating Procedures to Prevent Its Occurrence

AIR4762A (Current)05/24/2016

This Aerospace Information Report (AIR) describes conditions under which freezing (frozen) brakes can occur and describes operating procedures which have been used to prevent or lessen the severity or probability of brake freezing. This document also identifies design features that some manufacturers implement to minimize the occurrence of freezing brakes. This document is not an Aerospace Recommended Practice (ARP) and therefore does not make recommendations based on a consensus of the industry. However, part of this document’s purpose is to describe the design and operational practices that some are using to minimize the risk of frozen brakes. NOTE: The following information is based upon experience gained across a wide-range of aircraft types and operational profiles, and should NOT take precedence over Aircraft Flight Manual or Flight Operations Procedures.

A-5A Wheels, Brakes and Skid Controls Committee

Carbon Brake Contamination and Oxidation

AIR5490A (Current)04/12/2016

This document provides information on contamination and its effects on brakes having carbon-carbon composite friction materials (carbon). Carbon is hygroscopic and porous, and therefore readily absorbs liquids and contaminants. Some of the contaminants can impact intended performance of the brake. This document is intended to raise awareness of the effects of carbon brake contamination and provide information on industry practices for its prevention. Although not addressed in this report, contaminants can cause problems with other landing system components including tires.

A-5A Wheels, Brakes and Skid Controls Committee

The Unified Relationship between Torque and Gear Ratio and Its Application in Multi-Step Automatic Transmissions

2016-01-109804/05/2016

The market demands for CO2 reduction and fuel economy have led to a variety of new gear set concepts of automatic transmissions with 4 planetary gear sets and 6 shift elements in recent years. Understanding the relationship between the torque of clutch and brake and gear ratio in the design stage is very important to assess new gear set concepts and to set up the control strategy for enhancing shift quality and to reduce the heat generation of clutch and brake. In this paper, a new systematic approach is used to unify the relationship between torque and gear ratio during the gear shift for all multi-step planetary automatic transmissions. This study describes the unified concept model with a lumped inertia regardless of the specific transmission layout and derives the principal unified relationship equations using torque and energy analysis, which prove that the sum of brake torque is always gear ratio -1 in every in-gear. Based on the unified relationship equations, the relationship

Research on Electric Vehicle Braking Force Distribution for Maximizing Energy Regeneration

2016-01-167604/05/2016

The driving range of the electric vehicle (EV) greatly restricts the development of EVs. The vehicles waste plenty of energy on account of automobiles frequently braking under the city cycle. The regenerative braking system can convert the braking kinetic energy into the electrical energy and then returns to the battery, so the energy regeneration could prolong theregenerative braking system. According to the characteristics of robustness in regenerative braking, both regenerative braking and friction braking based on fuzzy logic are assigned after the front-rear axle’s braking force is distributed to meet the requirement of braking security and high-efficient braking energy regeneration. Among the model, the vehicle model and the mechanical braking system is built by the CRUISE software. The paper applies the MATLAB/SIMULINK to establish a regenerative braking model, and then selects the UEDC city cycle for model co-simulation analysis. Finally, the feasibility of the proposed control

Liu, Wenchao, Chen, Guoying, Zong, Changfu, Li, Chunshan

Design and Simulation Analysis for an Integrated Energy-Recuperation Retarder

2016-01-045804/05/2016

Vehicle auxiliary braking system is very significant to the brake safety. The eddy current retarder (ECR) has a good braking performance, but the braking torque would fade under high speed domain. In the contrary, the regenerative brake (RGB) could provide a satisfied braking performance in high speed domain. However, the braking torque in low speed domain is insufficient. This paper proposed a novel concept of the integrated energy-recuperation retarder (IEER), which would take advantage of the merits of both the ECR and the RGB to have a steady braking performance in all-speed domain. The IEER integrates the structures of rotary eddy current retarder (RECR) and the RGB, both of which share a stator. Braking torque of the IEER produced by stator core and armature-windings can stack together, and therefore the IEER can provide greater braking torque than the RECR. Besides, the IEER can recover electric energy from armature-windings. The IEER can weaken the recession of braking torque

Li, Jiawei, Tan, Gangfeng, Ji, Yangjie, Zhou, Yongchi, Liu, Ziang, Xu, Yingxiao

Further Research into the Role of the Caliper Piston in Brake Roughness

2015-01-266709/27/2015

Previously published research [1] covering the role of piston material properties in brake torque variation sensitivity and roughness concluded that phenolic pistons have significantly higher low-pressure range compliance than steel pistons, which promotes lower roughness propensity. It also determined that this property could be successfully characterized using a modern generation of direct-acting servo hydraulically actuated brake component compression test stands. This paper covers a subsequent block of research into the role of the caliper piston in brake torque variation sensitivity (BTV sensitivity) and thermal roughness of a brake corner. It includes measurements of hydraulic stiffness of pistons in a “wet” fixture, both with and without a brake pad and multi-layer bonded noise shim. Inertia dynamometer measurements of BTV sensitivity against a machined 20-micron thickness variation rotor with multiple (prototype) phenolic piston geometries, as well as steel pistons with two

Antanaitis, David B., Ciechoski, Chris, Riefe, Mark

Effect of Material and Dimensional Homogeneity on Thermo-mechanical Deformation of Brake Discs during High-speed Braking

2015-01-267309/27/2015

Brake judder is one of the most serious problems in automotive-brake systems, and brake discs play a significant role in judder. There are two types of brake judder: cold and hot. Hot judder is caused by the thermo-mechanical deformation of a disc rotor due to high-speed braking. There are several causes and shapes of the deformation, e.g., coning and circumferential waviness. Circumferential waviness of brake discs is typically found as a butterfly shape in a 2nd rotational-order and corrugation (or hot-spotting) around a 10th order, which are caused by thermo-mechanical buckling. The author focused on the effects of material and dimensional homogeneity on the transient and permanent wave-like deformation of ventilated discs in low rotational-orders during repetitive high-speed braking. The tested discs were in two groups that had the same design and gray-cast-iron class but were cast in two foundries by using horizontal- and vertical-molding machines, respectively. Consequently the

Okamura, Toshikazu

Configuration of Brake Components

2015-01-266809/27/2015

The hydraulic brake products like brake calipers, master cylinders and boosters are the foundation of today complex vehicle brake systems. The state of the art application leads very often to an individual design, due to the fulfillment of customer requirements within the available installation space. Also the enormous pressure on cost and time require optimized design processes. Therefore Continental developed the product configuration software CoBra. Within this software tool, the engineering is able to react very fast on demands. Starting with the brake sizing parameters and the customer interface definition, CoBra supports the design engineer to select the necessary components and positioning them accordingly, considering the actual design standards. The data based configuration software collects all necessary design parameters and provides an export to parametric CAD start up models. Therefore a high level of data quality can be achieved which allows to couple further design and

Ungethuem, Ulrich, Simon, Dirk

Accuracy of Sensor-Less Control of an Electro-Mechanical Brake

2015-01-270409/27/2015

At first glance a friction brake should be controlled by normal force to produce predictable brake force. Controlling an actuator (and hence brake pad) position basically seems to introduce uncertainties to normal force and brake force, because at first view the position tells little about actual normal force. The electro-mechanical brake (EMB) of Vienna Engineering (VE) can be operated by position-control, either without force sensor (saving costs) or even with a true brake torque sensor. For position control a relation between actuator position and normal force is used. When pad wear is correctly adjusted a certain actuator position produces a given deformation and at known elasticity the deformation produces a defined normal force. In the VE-EMB this relation uses a three-dimensional curve and includes temperature influence of the coefficient of friction, thermal expansion and thermal elasticity change. The temperatures for this control can't directly be measured at normal vehicles

Putz, Michael Herbert, Seifert, Harald, Zach, Maximilian, Schiffer, Markus, Peternel, Jure

Study on the Braking Torque Allocation of the ABS Based on the Frequency of the Electro-Hydraulic Brake

2015-01-270309/27/2015

Study on the braking torque allocation of the ABS (Anti-lock Brake System) of the electro-hydraulic brake system in the distributed drive electric vehicles, using a hierarchical control structure, of which the lower controller takes a braking torque allocation strategy based on frequency, so as to achieve a good braking effect. The lower controller uses the strategies which are based on the filter principle or the weighted least squares algorithm. To the former, Butterworth filter is selected to execute the braking torque allocation. Then the ABS braking torque allocation strategy based on Butterworth filter and the weighted least squares are designed and analyzed respectively, finally their braking effects are simulated and contrasted in Simulink and AMESim.

Zhuo, Guirong, Yu, Fei, Ren, Yilin

The Development of Brake Feel with Variable Servo Ratio Control

2015-01-269609/27/2015

We had developed Electric Servo Brake System, which can control brake pressure accurately with a DC motor according to brake pedal force. Therefore, the system attains quality brake feeling while reflecting intentions of a driver. By the way, “Build-up” is characteristics that brake effectiveness increases in accordance with the deceleration of the vehicle, which is recognized as brake feeling with a sense of relief as not to elongate an expected braking distance at a downhill road due to large-capacity brake pad such as sports car and large vehicles. Then, we have applied the optical characteristic control to every car with Electric Servo Brake System by means of brake pressure control but not brake pad. Hereby, we confirmed that the control gives a driver the sense of relief and the reduction of pedal load on the further stepping-on of the pedal. In this paper, we describe the development of brake feel based on the control overview.

Brake Pedal Feel Control Model

2015-01-267409/27/2015

Customer perception of brake pedal feel quality, depends on both the customer's subjective judgment of quality and the actual build quality of the brake system. The brake performance stability represents an important aspect of a vehicle performance and its quality of use. This stability is needed especially in brake by wire system and braking system with regenerative braking. In order to provide stable braked pedal feel i.e. consistent the brake performance against the brake pedal travel, the model of the brake performance versus the brake pedal travel needs to be established. In this paper new hybrid neuro-genetic optimization model was developed for dynamic control and optimization of the disc brake performance during a braking cycle versus the brake pedal travel. Based on such model, the brake performance optimization of the passenger car has been provided against the brake pedal travel. It enables different setting of the brake pedal feel for wanted braking system responses which

Aleksendric, Dragan, Cirovic, Velimir, Smiljanic, Dusan

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