Browse Topic: Brake master cylinders

Items (176)

Service Maintenance of SAE J1703 and SAE J1704 Brake Fluids in Motor Vehicle Brake Systems

J1707_202106 (Current)

6/10/2021

This SAE Recommended Practice provides basic recommendations for dispensing and handling of SAE J1703 and SAE J1704 Brake Fluids by Service Maintenance Personnel to assure their safe and effective performance when installed in or added to motor vehicle hydraulic brake actuating systems. This document is concerned only with brake fluid and those system parts in contact with it. It describes general maintenance procedures that constitute good practice and that should be employed to help assure a properly functioning brake system. Recommendations that promote safety are emphasized. Specific step-by-step service instructions for brake maintenance on individual makes or models are neither intended nor implied. For these, one should consult the vehicle manufacturer’s service brake maintenance procedures for the particular vehicle. Vehicle manufacturer’s recommendations should always be followed.

Brake Fluids Standards Committee

Low Water Tolerant Brake Fluids

J1705_202105 (Current)

5/28/2021

This SAE Recommended Practice was prepared to provide engineers, designers, and manufacturers of motor vehicles with a set of minimum performance requirements in order to assess the suitability of silicone and other low water tolerant type brake fluids (LWTFs) for use in motor vehicle brake systems. These fluids are designed for use in braking systems fitted with rubber cups and seals made from styrene-butadiene rubber (SBR), or a terpolymer of ethylene, propylene, and a diene (EPDM). In the development of the recommended requirements and test procedures contained herein, it is concluded that the LWTFs must be functionally compatible with braking systems designed for SAE J1703 and SAE J1704 fluids. To utilize LWTFs to the fullest advantage, they should not be mixed with other brake fluids. Inadvertent mixtures of LWTFs with fluids meeting SAE J1703 are not known to have any adverse effects on performance, but not all combinations have been tested. Vehicle manufacturer’s recommendations should be followed where indicated. These fluids are not necessarily suitable for use in central hydraulic or pumped systems and are not intended for use below temperatures of -50 °C (-58 °F). Brake fluids covered under this document are not required to tolerate water and extreme caution should be exercised to prevent accidental entry of water which might lead to brake failure. Other performance characteristics of these LWTFs not covered in this document are discussed in Appendix A.

Brake Fluids Standards Committee

Graphic Symbols for Aircraft Hydraulic and Pneumatic Systems

AS1290C (Current)

2/12/2021

This SAE Aerospace Standard (AS) provides a system of graphic symbols and line codings that are intended primarily for usage in hydraulic and pneumatic system schematic diagrams for all types of aircraft.

A-6 Aerospace Actuation, Control and Fluid Power Systems

Research on Compensation Redundancy Control for Basic Force Boosting Failure of Electro-Booster Brake System

2020-01-02164/14/2020

As a new brake-by-wire solution, the electro-booster (Ebooster) brake system can work with the electronic stability program (ESP) equipped in the real vehicle to realize various excellent functions such as basic force boosting (BFB), active braking and energy recovery, which is promoting the development of smart vehicles. Among them, the BFB is the function of Ebooster's servo force to assist the driver's brake pedal force establishing high-intensity braking pressure. After the BFB function failure of the Ebooster, it was not possible to provide sufficient brake pressure for the driver's normal braking, and eventually led to traffic accidents. In this paper, a compensation redundancy control strategy based on ESP is proposed for the BFB failure of the self-designed Ebooster. Firstly, introduced the working principle of Ebooster and ESP, and a suitable pressure-building circuit was selected for the dual brake actuator system; Secondly, after the BFB failure of Ebooster, the rule-based strategy of braking awareness recognition was designed. Thirdly, a layered closed-loop compensation control strategy is designed based on the ESP to restore the pressure building capacity of the hydraulic system. Finally, based on dSPACE products, a hardware-in-the-loop (HiL) experimental bench with dual brake actuators including ESP and Ebooster was built for algorithm verification. The HiL experiment results show that after the BFB failure of Ebooster, the designed compensation redundancy control algorithm can restore the Pressure-Volume (P-V) characteristics of the brake system just like Ebooster's conventional BFB mode, and improve vehicle driving safety.

Zhao, Jian, Chen, Zhicheng, Zhu, Bing, Wu, Jian

Simulation of Curved Road Collision Prevention Warning System of Automobile Based on V2X

2020-01-07074/14/2020

Li, Xuanhe, Wu, Jian, He, Rui, Zhu, Bing, Zhao, Jian, Zhou, Hang

Influence of Pads and Brake Disc wear on Brake Squeal Noise

2019-36-00051/13/2020

The present work aims to investigate the influence of wear of the pads and brake disc on the brake squeal behavior with the help of the Finite Element tool. Brake discs basically work by the pressure of the brake pads against a rotating disc. The friction between the pads and the disc causes the latter to decelerate, but it can also cause dynamic instabilities of the system giving rise to noises. Among the main noise in vehicle brake systems, there is the squeal noise, which is usually associated with the coupling of two neighboring natural modes. One possible way to identify unstable modes is by extracting complex eigenvalues from the system. An unstable mode can be identified when, in the result of the extraction of the complex eigenvalues, the real part of the eigenvalue is positive. In the present work, a brake system (disc and positioned pads and their respective materials and friction coefficients) was duly modeled and validated. The validation was done by means of a correlation between the frequency of the noises found experimentally and the frequency of the unstable modes found in the virtual model. A parametric analysis was performed simulating the wear of the disks and pads to understand the effect of the mass variations and stiffness on the instability of the system. According to the results found in the analyzes that simulate the wear, with the decrease, mainly the thickness of the brake pads, there was an increase of numbers of unstable modes, that is, the brake system is more prone to squeal generation.

dos Anjos, Marco Túlio Batista, Gutiérrez, Juan Carlos Horta, Ferreto, Cláudio Junior, Silva, Felipe Dornellas, Donadon, Lázaro Valentin

Performance Gains of Load Sensing Brake Force Distribution in Motorcycles

2019-28-242611/21/2019

Commercial motorcycles and scooters incorporate independent circuits for front and rear brake actuation, thus precluding load-dependent brake force distribution. In all cases of manual brake force modulation between the front and rear wheels, there is poor compensation for the changes in wheel loads on the account of longitudinal weight transfer, thus making it challenging to provide an adequate braking force to each wheel. The ratio in which the braking force should be distributed between the front and the rear wheels is dependent on the motorcycle’s geometry, weight distribution, mechanical sizing of braking system components, and is a variable based on the instantaneous deceleration. This connotes that a fixed bias of front and rear braking forces can be optimized only for a narrow range of motorcycle’s deceleration. Maximum braking performance occurs just prior to wheel lock-up, as a sliding tire provides less grip than a rolling tire. This is also the scenario when both the tires are doing the maximum work in decelerating the motorcycle. Therefore an optimal brake force distribution is one that locks both the wheels at the same instant. In practice, however, a rider would avoid a front wheel lock-up as it would make the motorcycle challenging to steer. In theory, an apt distribution of the braking forces between the front and rear wheels maximizes the overall braking efficiency of the motorcycle whilst reducing its stopping distance. This paper examines the plausible performance gains of load sensing brake force distribution in a motorcycle.

Chakraborty, Apurva

Compressible Brake Fluid Turbulent Flow Simulation and Experimental Verification on Brake Bleeding Performance Improvements of an EPB Caliper

2018-01-187610/5/2018

Brake bleeding is the process of removing air bubbles present on hydraulic brake systems from the master cylinder to the calipers of a vehicle, including the brake pipes and hoses. This is very important procedure affecting on brake performance, but still has been a key issue in automobile industry for last decades because reaching best bleeding performance has a limit that there is always remaining air in brake system. In this paper, it is reported on numerical and experimental investigations into the topic of bleeding performance improvements. Compressible brake fluid turbulent flow simulation with two-phase mixture model was performed to investigate the details of the bleeding performance drop during its cycles. The rig test of the hollow cylinder was carried out in order to secure the brake consumption amount curve whose results were used for the criterion of the parametric simulations using Tait equation to estimate the property of the brake fluid with the bulk modulus of 19,535 bar and 0.00016%. It was observed that the experimental curve data from the rig test of the hollow cylinder is divided into two regions with high and low compressibility, and more volume change in the low region below 1 bar is required to gain the same pressure variation due to the compression of the tiny air bubbles. The improved design of the nut-spindle with 6 holes in circumferential direction was drawn for the better removal of the trapped air. The simulation of the improved model showed the manual bleeding performance improvements of 18.9% than the baseline model due to the holes effect on circulation of the trapped air. It was experimentally verified that the air bubbles from their visualization are compressed to form the smaller size bubbles in the process of pressurization and gathered on the topmost side, whereas they are again expanded to form the larger size bubbles in the process of pressure release and spread into the wider space. The bleeding performance for the improved model was also experimentally verified to be effective up to approximately 51% through the caliper performance tester.

Mo, Jang-Oh

Comparison of Different Variable Braking Force Systems

2018-01-186510/5/2018

An automobile braking system has a crucial role in the safety of the passengers and riding quality of the vehicle. The braking force mainly depends on the normal reaction on the wheel and the coefficient of adhesion between the tire and the road surface. The required braking force for a vehicle varies with the load on the vehicle. If the applied braking force is greater than the required brake force, wheel gets locked which results in increased stopping distance. In order to prevent the wheel lock at low load conditions or deficient braking force at extremely high load conditions, a variable braking force system is developed. Whenever a motorcycle is loaded, the normal reaction on the rear wheel is increased. Thus, the amount of braking force required to halt the motorcycle with minimum stopping distance and stability of the motorcycle is based on the pillion load on the motorcycle. Hence, the amount of braking force developed between the road surface and the tire is varied in the variable braking force system. In this research work, three different variable brake force systems are compared. The different braking force systems are obtained by varying the effective disc radius or varying the pedal leverage or varying the area of piston. Simulation on the vehicle stopping distance is performed to compare the stopping distance of conventional braking system to Variable braking force system.

Subramanian, Chidambaram, Vinayaga Sundaram, Ganesh

Speed Tracking Control for All-Terrain Vehicle Considering Road Slope and Saturation Constraint of Actuator

2017-01-19539/23/2017

In this paper, a speed tracking controller is designed for the All-terrain vehicles. The method of feedforward with state variable feedback based on conditional integrators is adopted by the proposed control algorithm. The feedforward is designed considering the influence of the road slope on the longitudinal dynamics, which makes the All-terrain vehicles satisfy the acceleration demand of the upper controller when it tracks the desired speed on the road with slope varying greatly. The road slope is estimated based on a combined kinematic and dynamic model. This method solves the problem that road slope estimation requires an accurate vehicle dynamic model and are susceptible to acceleration sensor bias. Based on the vehicle dynamic model and the nonlinear tire model, the method of conditional integration is used in the state variable feedback, which considers the saturation constraint of the actuator with the intention of preventing the divergent integral operation. The control algorithm proposed in this paper can meet the requirements of vehicle speed tracking by controlling the engine driving torque and EHB brake fluid pressure. In the end, the speed tracking control algorithm is verified by the real vehicle tests, which makes the All-terrain vehicles track the desired speed effectively and acquire the desired acceleration. Furthermore, it ensures that the tracking error varies within the range of ±2km/h, meeting the requirements of national vehicle test standards.

Bai, Manfei, Xiong, Lu, Fu, Zhiqiang, Zhang, Renxie

Modeling, Simulation and Experimental Analysis of Brake Pedal Feel for Passenger Car

2017-01-13713/28/2017

Brake pedal feel plays an important role in the driver's comprehensive subjective feeling when braking, which directly affects the active safety and riding comfort of passenger car. A systematical mathematical model of the vehicle brake system is built in according with the structure and system characteristics of hydraulic servo brake system. A complete hydraulic servo brake system simulation model composed of brake pedal, vacuum booster, brake master cylinder, brake pipe, brake wheel cylinders, brake calipers is established in AMESim. The effects of rubber reaction plate stiffness, rubber valve opening, brake master cylinder piston, brake caliper, brake pipe deformation and friction liner deformation on brake pedal feel are considered in this model. The accuracy of this model is verified by real road vehicle tests under static and dynamic two different conditions. The influence of six structural parameters of vacuum booster, brake pipe and brake caliper on brake pedal feel are analyzed in detail. Finally, based on the evaluation system of BFI, the influence degree of different factors in different levels on the brake pedal feel are discussed through the orthogonal experiment design. The optimal scheme of brake pedal feel is put forward based on the sensitivity of various factors and validated by experiment. This study can serve as important reference for obtaining the best brake pedal feel, and also provides the theoretical basis for pedal simulator design and braking intention recognition in Brake-by-wire.

Pan, Hao, Guo, Xuexun, Pei, Xiaofei, Dong, Xingzhi

Anti-Lock Braking System Control Design on An Integrated-Electro-Hydraulic Braking System

2017-01-15783/28/2017

Two control strategies, safety preferred control and master cylinder oscillation control, were designed for anti-lock braking on a novel integrated-electro-hydraulic braking system (I-EHB) which has only four solenoid valves in its innovative hydraulic control unit (HCU) instead of eight in a traditional one. The main idea of safety preferred control is to reduce the hydraulic pressure provided by the motor in the master cylinder whenever a wheel tends to be locking even if some of the other wheels may need more braking torque. In contrast, regarding master cylinder oscillation control, a sinusoidal signal is given to the motor making the hydraulic pressure in the master cylinder oscillate in certain frequency and amplitude. Hardware-in-the-loop simulations were conducted to verify the effectiveness of the two control strategies mentioned above and to evaluate them. The simulation platform consists of the I-EHB hardware and software including CarSim and MATLAB/Simulink as well as LabVIEW serving as the communication tool. Conclusions can be reached in the light of testing results that both control strategies were able to achieve anti-lock braking under emergency situations. Compared with safety preferred control, master cylinder oscillation control performed better on the functionality of avoiding braking lock and the reduction of braking distance. Also, it is capable of working with electronic stability control systems (ESC) while safety preferred control cannot.

Liu, Tianyang, Yu, Zhuoping, Xiong, Lu, HAN, Wei

Strength and Durability Testing for Automotive Hydraulic Brake Components

J2995_201703 (Current)

3/13/2017

To assess the strength and durability for hydraulic brake components as a function of test conditions. These conditions may include: braking torque, hill-holding, braking forces, hydraulic pressure, brake temperatures, environmental and corrosion effects, vibration, and time. This RP includes a systematic reference to other test methods and provides new test methods for durability life prediction based on the VDA 311 for operating strength for brake calipers. When using AK load collectives from vehicle testing for life prediction, the nominal vehicle life corresponds to 300000 km. Braking torques and forces take into account inputs from non-ABS, ABS, EPB, and ESC systems. It also applies to gasoline, diesel, hybrid, and electric vehicles. This RP applies to vehicles below 4540 kg of GVWR. With the appropriate engineering review and assessment for a given test program, this RP can apply (or be used) to scale the duty cycle (or special collective) to reflect regional, on-road special applications, or vehicles up to 7 tons of GVWR. Except for the AK load collectives, which have proven correlation to customer usage, the damage content of other procedures requires (a) the quantification with actual laboratory testing to develop the corresponding S/N curves, and (b) the calculation of the equivalent damage at the test conditions for a given load collective. The hydraulic components covered by this RP include: a Non-vacuum apply system (brake booster and master cylinder) b ABS modules c Service, IPB, and EPB calipers d Proportioning valves e Wheel cylinders This RP has an accompanying electronic appendix with the tabular presentation as a spreadsheet of different test procedures by type and by component.

Hydraulic Brake Components Standards Committee

Development of Advanced Braking System for Hybrid Sports Cars

2016-01-19239/18/2016

An advanced braking system had to be developed for a next-generation hybrid sports car with Sport Hybrid Super Handling All-Wheel Drive to achieve an intuitive brake feeling in a variety of driving conditions, ultimate track performance and reduction of CO2 emissions per vehicle. This paper outlines the integration of brake-by-wire with traditional high-performance braking hardware and describes the technology needed to achieve these goals. Key focus areas to generate these results were: brake feeling control, corner hardware specification considerations and brake cooling.

Dyar, Lorne R., Akita, Yuichiro, Paul, Scott, Lepito, Joseph, Ishikawa, Yoshio, Watanabe, Tomohiro

Model-Based Pressure Control for an Electro Hydraulic Brake System on RCP Test Environment

2016-01-19549/18/2016

In this paper a new pressure control method of a modified accumulator-type Electro-hydraulic Braking System (EHB) is proposed. The system is composed of a hydraulic motor pump, an accumulator, an integrated master cylinder, a pedal feel simulator, valves and pipelines. Two pressurizing modes are switched between by-motor and by-accumulator to adapt different pressure boost demands. A differentiator filtering raw sensor signal and calculating pedal speed is designed. By using the pedal feel simulator, the relationship between wheel pressures and brake force is decoupled. The relationships among pedal displacement, pedal force and wheel pressure are calibrated by experiments. A model-based PI controller with predictor is designed to lower the influences caused by delay. Moreover, a self-tuning regulator is introduced to deal with the parameter’s time-varying caused by temperature, brake pads wearing and delay variation. To verify the controller validity, a Rapid Control Prototype (RCP) test environment based on dSPACE is built. Self-designed HCU and pedal feel simulator are installed in test bench. The close loop test results of pressure tracking are plotted and analyzed by contrasting normal PI controller and proposed controller. The conclusion indicates that the proposed controller can reach a balance of rapidity and accuracy, meanwhile the operating time and energy consumption are also reduced.

Xiong, Zhe, Pei, Xiaofei, Guo, Xuexun, Zhang, Chengcai

Service Maintenance of SAE J1703 and J1704 Brake Fluids in Motor Vehicle Brake Systems

J1707_201609 (Historical)

9/13/2016

Brake Fluids Standards Committee

Power Assisted Braking Control Based on a Novel Mechatronic Booster

2016-01-16444/5/2016

This paper presents a power assisted braking control based on a novel mechatronic booster system. A brake pedal feel control unit is first discussed which includes a pedal emulator with an angular sensor to detect driver’s pedal travel, a signal processing module with a Kalman filter for sensor signal conditioning, and a driver braking intention detection and behavior recognition module based on the displacement and velocity of the pedal travel. A power assisted braking control is then presented as the core of the system which consists of controls on basic power assist, velocity compensation and friction compensation. The friction is estimated based on a generic algorithm offline. A motor controller is designed to provide the desired torque for the power assist. Finally, a novel mechatronic booster system is designed and built with an experimental platform set up with a widely adopted rapid prototype system using dSPACE products, such as MicroAutoBox, RapidPro, etc. Extensive experiments have been conducted which demonstrate the validity and effectiveness of the proposed control for the power assisted braking system.

Liu, Haizhen, Deng, Weiwen, He, Rui, Qian, Lei, Yang, Shun, Wu, Jian

Co-Simulation Research of Integrated Electro-Hydraulic Braking System

2016-01-16474/5/2016

A program of integrated electro-hydraulic braking system is proposed, and its structural composition and working principle are analyzed. According to the structural and mechanical characteristics of all key components, through some reasonable assumptions and simplifications, a motor, a brake master cylinder, four brake wheel cylinders, solenoid valves and an ESP (Electronic Stability Program) algorithm model is set up and simulations of typical braking conditions are carried out based on the Matlab/Simulink. Finally, after the assembly of each sub-model is complete and combining a vehicle which is set up in CarSim software environment, simulation tests and comprehensive performance analysis of the active safety stability control for a vehicle in double lane change and single lane change situations are carried out respectively. According to the dynamic characteristic curves of system, the effects of different structural and control parameters on braking performance are analyzed. To improve overall braking performance, the results would help to match and optimize system parameters, and provide reference data for further clarifying ideas and goals of parameters optimization. The vehicle control results show that the proposed integrated electrohydraulic braking system has characteristics of a simple structure, very low cost, a good controllability, could be easily integrated with ABS (Anti-lock Braking System), TCS (Traction Control System), ESP and other intelligent electronic control braking functions, and has more extensive application value.

Li, Jing, Yang, Xiong, Miao, Hui, Shi, Zheng Tang

Development of an Electronically Controlled Brake System for Fuel-efficient Vehicles

2016-01-16644/5/2016

To solve various environmental problems, fuel-efficient vehicles that reduce CO2 emissions as well as exhaust gas emissions have been developed. In such vehicles, a regenerative brake is used to further reduce fuel consumption. Because the market size for such vehicles is expanding, a brake system is required that can be used in a wide range of vehicles extending from internal combustion engine vehicles (ICEVs) to electric vehicles (EVs). In addition, issues such as deceleration fluctuation and brake pedal fluctuation arise because the regenerative brake force is dependent on the vehicle speed. This paper presents a brake system configuration and its element technologies that can replace existing brake systems in different vehicles ranging from ICEVs to EVs. The proposed system can realize a regenerative cooperative brake not only by replacing the brake booster unit but also without replacing the modulator. The advantages of this system are the maximization of regenerative efficiency, assurance of system reliability, and better brake feel.

Masuda, Yoshio, Yamasoe, Yosuke, Kuki, Yosuke, Okano, Takahiro, Uchida, Kiyoyuki

Configuration of Brake Components

2015-01-26689/27/2015

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 simulation modules. Today all caliper types and the master cylinders are part of the actual software version. In summary we can state that CoBra, as the basis for the start of each caliper application, has a high impact on the standardization approach. The early integration of design rules, manufacturing standards and the attached CAD / CAE process reduces failure modes and gives the engineering more time to concentrate on the project specific optimizations.

Ungethuem, Ulrich, Simon, Dirk

Antilock Brake Control System for Four-Wheel-Drive Electric Vehicle with Electro-hydraulic Braking based on Precise Control of Hydraulic Braking Force

2015-01-15734/14/2015

With the objective to regulate hydraulic pressure accurately by controlling high speed on-off valve (HSV), finite element models are parameterized based on measured parameters of an ABS hydraulic actuator unit (HCU). The data that reflects transient electromagnetic characteristics of HSV is selected with finite element numerical simulation. Taking full advantage of those data, accurate physical models of HSV are built with other parts of hydraulic braking system. Then a new system structure is proposed to control hydraulic pressure. Not only do simulation results show ideal control effect, but also hydraulic braking system can be controlled under arbitrary input signal. Accordingly, hydraulic braking force can achieve fine regulation. Finally, the hydraulic braking system is utilized to design antilock brake control system for four-wheel-drive electric vehicle with electro-hydraulic braking. That kind of system is established on the basis of hierarchical control structure. By what is called a frequency assignment approach, the lower controller coordinates the total braking torque, which is calculated by sliding mode control algorithm in the upper controller. During braking force distribution, motors execute the higher frequency torque commands, while hydraulic system responses for the lower frequency ones. System's effectiveness is validated under emergent braking based on AMESim-Simulink co-simulation.

Zhuo, Guirong, Shen, Hui, Wu, Shenchen, Ren, Yilin

Hardware-in-the-loop Simulation for an Integrated Braking System

2015-01-15824/14/2015

Comparing with traditional braking systems of automobiles, the brake-by-wire (BBW) system has a faster dynamic response and is more suitable for applications that facilitate regenerative braking. As the two main categories of BBW systems, the well-known electro-hydraulic braking system and electro- mechanical braking system are not compact enough and their fail-safe function has always been a worrying aspect. A new BBW system called integrated braking system (IBS) by employing the hydraulic multiplex method was proposed in recent years. The IBS implements power-assisted braking and active braking by means of just an integrated unit. It can certainly be used for ABS, ASR and ESC systems for building up and reducing brake pressure. Presented in the paper is a new structure of IBS, which is mainly composed of a motor, ball screw, master cylinder and four 2/2-way valves. The main parameters of the system and performance requirements of the motor are determined by means of simulation in MATLAB/Simulink. The prototype and controller of the system had been developed, and the hardware-in-the-loop simulation (HILS) test rig was built. Vehicle dynamics model was performed in veDYNA to provide variables such as slip rate and wheel speed to the controllers. The HILS results show that the single wheel cylinder pressure regulation frequency can reach 20Hz. Limited by the performance of the motor, the system can only realize part of ABS functions.

Yong, Jiawang, Gao, Feng, Ding, Nenggen, Wang, Wei, Hu, Xianrong

Brake Master Cylinder Reservoir Diaphragm Gasket

J1605_201411 (Current)11/26/2014

This SAE Standard covers performance requirements and methods of test for master cylinder reservoir diaphragm gaskets that will provide a functional seal and protection from outside dirt and water.

Hydraulic Brake Components Standards Committee

ASURT Formula Student Brake Design

2014-01-24879/28/2014

The Braking System is the most crucial part of the racing vehicle. There is no doubt, that if only one minority failure in the braking system took place, this would be more than enough reason to cause the racing team disqualification from the competition. Time is the main and the most important criteria for any racing competition; on the other hand the formula student “FS UK SAE” competition care the most about developing the automotive engineering sense in the students by putting them under strict rules normally taken from the original version “formula 1” to encourage their creativity to reach the optimum performance under these strict rules. One of the most important rules is “No Braking by wire”, and the obvious consequences are more stopping distance and time. Braking distance is a critical facture in achieving racing success in a competitive domain. This report will cover using the bias bar, dynamic weight distribution “before and after braking” and carefully choosing the braking and suspension system components dimensions, in order to fulfill the main functions of “ABS and EBD” which are preventing the wheels from lock-up and preventing side skid of the vehicle during cornering in the different dynamic tests with full consideration of the maximum approachable deceleration of the vehicle without locking up without using any kind of electronic “actuators or control”. Mathematical model “Matlab” and Physical model “AME SIM” will be used to support the report's results.

Barakat, Mohamed Samy

Development of Composite Brake Pedal Stroke Simulator for Electro-Hydraulic Braking System

2014-01-01174/1/2014

A brake pedal stroke simulator for Electro-hydraulic Braking System (EHBS) was developed to ensure the comfort braking pedal feel for the brake-by-wire system. An EHBS with an integrated master cylinder was proposed, and a composite brake pedal stroke simulator was designed for the EHBS, which was comprised of two inline springs and a third parallel one. A normally closed solenoid valve was used to connect the master cylinder booster chamber and the stroke simulator. The suitable brake pedal stroke was achieved by three stages of these springs' compression, whereas the solenoid valve was shutdown to enable mechanical control of the service brakes when electrical faults appeared. The pedal stroke simulator and the EHBS were modeled in MATLAB/SIMULINK-AMESim, and then the pedal stroke characteristic including the depressing and releasing process and its influencing factors, namely the preload force of the return spring, the cross-sectional area of the solenoid valve orifice, piston damping coefficient, and the pressure booster ratio were analyzed during the normal and failsafe mode. A bench test and hardware-in-the-loop (HIL) simulation were built to verify the stroke simulator performance. The simulation and test results show that the proposed pedal stroke simulator can meet the requirements of EHBS with improved braking comfort and driving safety.

Liu, Yang, Sun, Zechang, JI, Wenbin

Development of Regenerative Cooperative Braking System with Conventional ESC

2014-01-03314/1/2014

HEV and EV markets are in a rapid expansion tendency. Development of low-cost regenerative cooperation brake system is needed in order to respond to the consumers needs for HEV and EV. Regenerative cooperation brake system which HEV and EV are generally equipped with has stroke simulator. We developed simple composition brake system based on the conventional ESC unit without the stroke simulator, and our system realized a low-cost regenerative cooperation brake. The key technologies are the quiet pressurization control which can be used in the service application, which is to make brake force depending on brake travel, by gear pump and the master cylinder with idle stroke to realize regenerative cooperation brake. Thanks to the key technologies, both the high regenerative efficiency and the good service brake feeling were achieved.

Naito, Masayuki, Koike, Yasuhiro, Osaki, Shintaro, Morishita, Shinichiro, Quan, Nanhao

Thermomechanical Stress Analysis of Vehicles Gray Cast Brake

2013-01-91167/15/2013

The main purpose of this study is to analyze the thermomechanical behavior of the dry contact between the brake disc and pads during the braking phase. The simulation strategy is based on computer code ANSYS11. The modeling of transient temperature in the disc is actually used to identify the factor of geometric design of the disc to install the ventilation system in vehicles. The thermal-structural analysis is then used with coupling to determine the deformation and the Von Mises stress established in the disk, the contact pressure distribution in pads. The results are satisfactory when compared to those of the specialized literature.

Belhocine, Ali, Bouchetara, Mostefa

Hydraulic Wheel Cylinders for Automotive Drum Brakes

J101_201307 (Current)7/9/2013

This document specifies minimum performance and durability requirements for satisfactory vehicle usage, and it is applicable to wheel cylinder assemblies from commercial production, after production shipment, shelf storage, and remanufacture (factory rebuild).

Hydraulic Brake Components Standards Committee

Thermomechanical Stress Analysis of Vehicles Gray Cast Brake

2013-01-08774/8/2013

Belhocine, Ali, Mostefa, Bouchetara

Vehicle Powertrain Test Bench Co-Simulation with a Moving Base Simulator Using a Pedal Robot

2013-01-04104/8/2013

To evaluate driver perception of a vehicle powertrain a moving base simulator is a well-established technique. We are connecting the moving base simulator Sim III, at the Swedish National Road and Transport Research Institute with a newly built chassis dynamometer at Vehicular Systems, Linköping University. The purpose of the effort is to enhance fidelity of moving base simulators by letting drivers experience an actual powertrain. At the same time technicians are given a new tool for evaluating powertrain solutions in a controlled environment. As a first step the vehicle model from the chassis dynamometer system has been implemented in Sim III. Interfacing software was developed and an optical fiber covering the physical distance of 500 m between the facilities is used to connect the systems. Further, a pedal robot has been developed that uses two linear actuators pressing the accelerator and brake pedals. The pedal robot uses feedback loops on accelerator position or brake cylinder pressure and is controlled via an UDP interface. Results from running the complete setup showed expected functionality and we are successful in performing a driving mission based on real road topography data. Vehicle acceleration and general driving feel was perceived as realistic by the test subjects while braking still needs improvements. The pedal robot construction enables use of a large set of cars available on the market and except for mounting the brake pressure sensor the time to switch vehicle is approximately 30 minutes.

Andersson, Anders, Nyberg, Peter, Sehammar, Håkan, Öberg, Per

Impact of Pad Wear on the Pressure Dynamics of a Vehicle Braking System

2012-01-18979/24/2012

A vehicle braking system is used to provide acceptable drivability of the vehicle and ensure safety in different emergency situations that the vehicle may encounter. The braking system is used also as an integrated sub-system in many other important vehicle driving systems such as traction control, adaptive cruise control, accident avoidance and other vehicle systems in which the braking system plays an important role. This paper is dedicated to provide an accurate and at the same time simple enough hydro-mechanical braking system mathematical model that takes brake pad wear impact on the system pressure dynamics into consideration. A wear simulation procedure based on the concept of Archard's wear law is used and integrated in the nonlinear braking system model with flow compressibility taken into consideration. The presented model simulation results and the experimental tests results show good agreement and validate the confidence in the proposed model. Also, a reduced order model of the full nonlinear one is presented. Both the full nonlinear model and the reduced order model show that increasing in the brake pad wear level increases the pressure spikes dynamics at the contact surface between brake pad and rotor disc and hence could leads to brake squeal and shortens the braking pad service life.

Haggag, Salem A., Abidou, Diaa

Automotive Hydraulic Brake System - Metric Tube Connections

J1290_201207 (Current)7/5/2012

This SAE Standard documents dimensional metric specifications for hydraulic brake system tubing with flared ends, threaded ports, and male tube nuts for the interconnection of major components in automotive hydraulic brake systems. The purpose of this document is to recommend preferred metrically dimensioned components (including alternative choices), that are intended to be functionally compatible with International Organization for Standardization Specification, ISO 4038. Some applications may require sizes of forms other than those shown herein, and this document does not preclude such other details when they are required.

Automotive Brake and Steering Hose Standards Comm

Remanufactured Hydraulic Master Cylinder for Motor Vehicle Brakes - General Characteristics and Test Procedure

J1693_201204 (Current)4/30/2012

Hydraulic Brake Components Standards Committee

Shelf Storage of Hydraulic Brake Components

J1825_201204 (Current)4/30/2012

This SAE Information Report is the listing of recommendations for shelf storage for hydraulic brake components. Included in brake components are wheel cylinders, master cylinders, combination valves, and disc brake caliper assemblies. This document is not a specification. This document embodies the analyses and experiences of many users and manufacturers. Where specific manufacturers' recommendations are made, those recommendations shall supersede the recommendations of this document. This document lists the successful procedures and practices associated with brake components based on long experience of a wide cross section of manufacturers and users. The practices are expected to be applied to all brake components where SAE standards are applicable.

Hydraulic Brake Components Standards Committee

Remanufactured Hydraulic Master Cylinder for Motor Vehicle Brakes - Performance Requirements

J1694_201204 (Current)

4/30/2012

This SAE Recommended Practice defines minimum requirements for general characteristics, performance, and durability. It is applicable to remanufactured assemblies (factory rebuild) only. This document applies to master cylinder assemblies and components of current established designs but does not cover fluid level sensors, integral proportioning valves, or those master cylinders used in anti-lock brake or traction control systems. These will be covered by other standards. The general characteristics and test procedure are specified in SAE J1693.

Hydraulic Brake Components Standards Committee

A Study on Prediction of the Brake Hoses Deformation Associated with a Vehicle Motion

2012-01-02244/16/2012

A Brake hose is a core part of the braking system that delivers the hydraulic pressure generated in the master cylinder to an actuator, which, in turns, creates braking force. The braking hose can be deformed in many different ways under various driving conditions, and it is essential that the brake hose should not experience any excessive deformation or interference with surrounding parts for durability and reliability. Despite of its importance, the brake hose design method has been very limited. Currently, it is tentatively designed with simple curves, such as a spline curve, then tested and modified with many different prototypes by doing a trial-and-error process due to the difficulty in simulating the behavior of the hose. This paper focuses on establishing the following processes to enhance the reliability of the drawing in the earlier stage of the vehicle development by a prompt and accurate simulation prediction; (1) Facilitating the design and modification of the hose path by developing a CAD template for the brake hose and fitting, (2) Coordinates of Body Fitting & Axle Fitting are extracted and calculated in order to create input data for a CAE software to perform a deformation analysis of brake hoses associated with the vehicle motion. The obtained CAE results are then converted into a CAD 3D model and used to check the interference with surrounding parts. The whole process is dedicated to two main objectives; the usability and reliability. Firstly, a unified GUI is developed to handle a data extraction, pre/post processing, 3D model generation, and interference check. Therefore, it allows even inexperienced engineers to easily get the analysis results and use it in the CAD environment. Secondly, by incorporating the beam cross-section model into the analysis, twist of a hose can be considered. The results are compared with the 3D scanning data of the hose installed in the actual vehicle for verification. The proposed processes and program can significantly decrease the computing time and increase the accuracy of the simulation for the presented example problems.

Kang, Moon-Won

Hydraulic Master Cylinders for Motor Vehicle Brakes Test Procedure

J1153_201202 (Current)2/17/2012

This SAE Standard specifies the test procedure to determine minimum performance and durability characteristics for master cylinder assemblies of current established designs, components of which conform to SAE Standards. It is applicable to new assemblies from commercial production and remanufacture (factory rebuild). The minimum performance and durability requirements are specified in SAE J1154.

Hydraulic Brake Components Standards Committee

Hydraulic Master Cylinders for Motor Vehicle Brakes - Performance Requirements

J1154_201202 (Current)2/17/2012

This SAE Standard specifies minimum performance and durability requirements for master cylinder assemblies of current established designs, components of which conform to SAE Standards. It is applicable to new assemblies from commercial production and remanufacture (factory rebuild). These performance requirements are based on those generally used by individual companies in the industry and have demonstrated satisfactory component field performance.

Hydraulic Brake Components Standards Committee

Service Maintenance of SAE J1703 and J1704 Brake Fluids in Motor Vehicle Brake Systems

J1707_201111 (Historical)

11/21/2011

Brake Fluids Standards Committee

Stability Control of Motorcycle

2011-32-055811/8/2011

We developed active control more suitable for sports riding than the previous electronic stability control system for enjoying sports riding by many users. One of them, the traction control system S-KTRC (Sports Kawasaki TRaction Control) uses the sensor output like not only the slippage calculated from the front and rear wheel speed but also engine speed, throttle position, and gear position etc. As the result, conditions of the motorcycle and rider's intention are calculated by ‘Motorcycle model’ in the ECU continuously. By this ‘Motorcycle model’, S-KTRC confirms the real time conditions and predicts the succeeded condition, every 5milliseconds to decide to govern torque. The ABS system KIBS (Kawasaki Intelligent anti-lock Brake System), it is possible to control the rear wheel's lift by using the pressure data of the front brake at the sudden braking operation. And by using the engine data, it is also possible to avoid the no preferable intervention by the ABS control, when the motorcycle goes into the corner under the shift down operation. Moreover, this system keeps the soft feedback feeling to rider's hand and foot by this precision ABS control. Each control system obtained good evaluation from beginner rider to expert rider. And these systems worked very well from every road surface condition.

Masuda, Yoshihiro, Matsuda, Yoshimoto

Development of New AMT Shift Speed Control System for Lexus LFA

2011-28-010310/6/2011

The development of the Lexus LFA focused on the pursuit of a passionate driving experience suitable for a super sports car. The shift speed control system in the LFA is an automated manual transmission (AMT) that uses an electrohydraulic actuator. The excellent shifting performance of the AMT was achieved by developing control technology that performs smooth, quick, and highly responsive shifting in accordance with the driving conditions. This was the result of repeated evaluations in both normal driving and on circuits featuring many acceleration, deceleration, and high-speed driving sectors. This paper describes the AMT shift speed control system and technology.

Shimizu, Masato, Inoue, Takashi, Miyazaki, Tsuyoshi

A Case Study of Reaction Time Reduction of Vehicle Brake System

2011-01-23799/18/2011

There has to be a good co-relation/ relationship between the pedal effort applied, pedal travel, deceleration level achieved and stopping distance for “good brake feel”. Brake feel also depend upon the time lag between the force applied on brake pedal and the response of braking system. Hence “brake feel” can be improved by reducing the response time of the brake system. Many vehicles are having “poor brake feel” complaints, pertaining to the above mentioned reasons. This paper relates to an improved brake system for automobile in which reduction in reaction time was done by artificially increasing differential pressure head across vacuum booster diaphragm. Brake booster is given an input of compressed air to the valve body during actuation, thereby increasing the differential pressure across the diaphragm. The compressed air is bled from turbocharger-intercooler of the vehicle which is stored in a reservoir, with one way valve, while cruising. However, same compressed air is utilized by the brake booster during brake application. Additionally, the compressed air reservoir acts as a cooler for stored air. By virtue of this mechanism, the overall reaction time of the brake booster reduces significantly for the same testing conditions. The whole circuit is provided with a pressure switch which detects any failure in the compressed air circuit and opens it up to the atmosphere, making booster work to its conventional capability. Using this concept on vehicle, marked reduction in stopping distance with improvement in “brake feel” was observed.

Gupta, Anshuman, Bisen, Badal G.

Modeling Drivers' Behavior During Panic Braking for Brake Assist Application, Using Neural Networks and Logistic Regression and a Comparison

2011-01-23849/18/2011

Researchers have shown that unskilled drivers fail to apply sufficient force on brake pedal in emergency. To solve this problem, Brake Assist System (BAS) is used to enhance the vacuum brake booster performance and results decrease in stopping distance. A major problem in BAS is to determine if a panic braking has been occurred or not. In this study, a model of drivers' behavior during a severe braking is created using both neural networks and logistic regression methods to determine the BAS threshold activation. Samples of brake pedal speed, Brake pedal displacement, and vehicle acceleration measured from panic and normal situations, will be fed for training neural networks and acquiring logistic regression equation. From both methods, the probability of a panic and normal situation will be determined. By using MATLAB software, the result from these two models is compared, and the one that is quicker in detecting panic situation and simple for implementation, will be chosen for BAS activation threshold.

Solaymani Roody, Samira

Hot Judder - An Investigation of the Thermo-Elastic and Thermo-Plastic Effects during Braking

2011-01-15755/17/2011

Thermo-elastic and thermo-plastic behaviour takes place with a disc brake during heavy braking and it is this aspect of braking that this paper considers. The work is concerned with working towards developing design advice that provides uniform heating of the disc, and equally important, even dissipation of heat from the disc blade. The material presented emanates from a combination of modeling, on-vehicle testing but mainly laboratory observations and subsequent investigations. The experimental work makes use of a purpose built high speed brake dynamometer which incorporates the full vehicle suspension for controlled simulation of the brake and vehicle operating conditions. Advanced instrumentation allows dynamic measurement of brake pressure fluctuations, disc surface temperature and discrete vibration measurements. Disc run-out measurements using non-contacting displacement transducers show the disc taking up varying orders of deformation ranging from first to third order during high speed testing. This surface interrogation during braking identifies disc deformation including disc warping, “ripple” and the effects of “hot spotting”. The mechanical measurements are complemented by thermal imaging of the brake, these images showing the vane and vent patterns on the surface of the disc. The results also include static surface scanning, or topographical analysis, of the disc which is carried out at appropriate stages during testing. The work includes stress relieving of finished discs and subsequent dynamometer testing. This identifies that in-service stress relieving, due to high heat input during braking, is a strong possibility for the cause of disc “warping”. It is also seen that an elastic wave is established during a braking event, the disc returning to its original form on release of the brake.

Fieldhouse, John David, Bryant, David, Talbot, Chris John

Development of an Electrically-Driven Intelligent Brake System for EV

2011-39-72115/17/2011

This paper presents the electrically driven intelligent brake system that has been developed for electric vehicles, which are expected to penetrate markets rapidly amid the ongoing energy paradigm shift. This brake system achieves a cooperative energy regeneration function and high responsiveness while providing braking performance, system reliability and vehicle mounting ease equal to that of conventional brake systems with a vacuum booster. This paper outlines the newly developed brake system and describes how to decide the target brake force which is achieved a regenerative braking capability for recovering energy efficiently without sacrificing braking.

Fujiki, Noriaki, Koike, Yuichi, Ito, Yoshinori, Suzuki, Goro, Gotoh, Shinnosuke, Ohtani, Yukio, Yamagucki, Tohma

Rubber Cups for Hydraulic Actuating Cylinders

J1601_201103 (Current)

3/16/2011

These specifications cover molded cups 51 mm (2 in) in diameter and under, compounded from high temperature resistant rubber for use in hydraulic actuating cylinders employing motor vehicle brake fluid conforming to the requirements specified in SAE J1703 and SAE J1705. These specifications cover the performance tests of hydraulic brake cups under specified conditions and do not include requirements relating to chemical composition, tensile strength, and elongation of the rubber compound. Disc brake seals are not covered by this document.

Hydraulic Brake Components Standards Committee

Selection of EPDM Elastomer in Brake Hose Application for Improved Brake System Performance

2010-01-188510/5/2010

Brake system has been considered as the most important safety system for a vehicle. Performance of the Brake system depends upon various factors like purity of brake fluid, material and construction of rubber hose, rubber seal performance etc. The purity of the brake fluid is one of the most vital factor and incompatibility of the rubber hose with brake fluid causes contamination of the brake fluid. This intern can cause shrinkage / swelling of master, slave cylinder rubber seals. The change in the dimensional of the rubber seals directly affects the performance of the brake system. In order to evaluate the performance of the brake system, Styrene Butadiene Rubber (SBR) and EPDM elastomers with different % of ethylene and varying ENB content were considered for brake fluid compatibility test. These rubber materials were tested in the different brands of DOT 3 brake fluid. Design of experiments has been carried out on EPDM material with different % of ethylene and varying ENB content to find out suitable and optimized combination of the rubber and brake fluid brands. The selected combination from the experiments has been taken further for component level tests. Traditionally, methods of test for the compatibility of brake fluid with rubber hose may not address the actual vehicle service conditions. To addresses the actual conditions; a new methodology has been developed. Hoses were successfully tested and their performance was compared in terms of volumetric expansion of rubber seal, brake fluid contamination, brake pedal sinking, and pedal efforts. This methodology can also be extended to detect contaminations in other types of fluids used in the automobile.

Sivakumar, Anandan, Sathaye, Asmita

Light Vehicle Dry Stopping Distance

J2909_201005 (Historical)

5/25/2010

This document establishes best practices to measure vehicle stopping distance on dry asphalt in a straight path of travel intended for the purpose of publishing stopping distance by manufacturers and media organizations. It is recommended that the test method within be adopted for all vehicles less than 10 000 lb (4536 kg) GVWR. This procedure is typically used with initial speeds of 100 km/h and 60 mph, but other speeds may be used.

Highway Tire Committee

Wear of Friction Material during Vehicle Braking

2009-01-10324/20/2009

An analysis of the vehicle braking, combining with the linear relation between wear and frictional work already investigated, was used to establish a wear equation. Initial braking velocity, the number of brakings per 1 km and pad thickness loss per 1000 km were determined by using taxis with identical car types and identical pad qualities. Based on the averaged experimental results and some normal braking conditions, the calculated average apparent specific wear rate through the equation was unexpectedly found to decrease firstly and then increase with the increase of average initial braking velocity. The pad friction properties relevant to the equation analysis were tested by using a dynamometer, followed by measuring wear as a function of temperature at three different initial velocities that equal the average initial braking velocities respectively. The measurement showed that wear was approximately proportional to initial velocity squared at the temperature of 50 to 300 °C, in good agreement with the equation. The estimated vehicle braking temperatures by comparing two different types of wear are close to the previously reported ones.

Zhang, Shaoyang, Chen, Weiping, Li, Yuanyuan

Kinematic Analysis of Multi-Axle Steering System for Articulated Vehicle

2009-26-00671/21/2009

Steering of non-driven axles of semi-trailer results in improvement of maneuverability during negotiating sharp turn and reduces tyre drag and wear by relieving locked-in forces in comparison to non-steered axles. Among few, command steering mechanism is reported to be most efficient method of steering of articulated vehicles. In this type, the axles of semi-trailer are steered in relation with the articulation of tractor. The articulation angle of tractor is sensed by an actuation mechanism integrated on trailer at fifth wheel location and transferred hydraulically to the steering linkages. Mathematical equations have been developed based on Ackerman's Principle to estimate theoretical steering angle when Tractor-Trailer negotiate any turn. Steering linkage geometry has been conceptualised, kinematically modelled and analysed by using ADAMS. Equations developed for theoretical steering angles are incorporated in ADAMS as run time functions. The difference in theoretical steering angles and angles obtained from kinematic analysis of linkage geometry are defined as steering errors. These errors are obtained from the kinematic analysis for all the axles of trailer for entire range of turning. Design of Experiment (DOE) has been carried out to minimize the steering error. The model has been made parametric to carry out DOE and also to incorporate any design changes with minimum modelling time. The mathematical equations are validated and steering error obtained from the analysis is also validated with published literature. Physical prototype made and validation carried out with tested data.

Chaudhuri, Sanjay, Saini, Vikram, Singh, Manmohan

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