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Service Maintenance of SAE J1703 and SAE J1704 Brake Fluids in Motor Vehicle Brake SystemsJ1707_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 FluidsJ1705_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
Low-Duty Inertia Dynamometer Hydraulic Brake Wear Test Procedures for Vehicles Above 4536 kg (10000 pounds) of GVWRJ3006_202005 (Current)5/26/2020
This Recommended Practice is derived from OEM and tier-1 laboratory tests and applies to two-axle multipurpose passenger vehicles, or trucks with a GVWR above 4536 kg (10 000 pounds) equipped with hydraulic disc or drum service brakes. Before conducting testing for a specific brake sizes or under specific test conditions, review, agree upon, and document with the test requestor any deviations from the test procedure. Also, the applicable criteria for the final test results and wear rates deemed as significantly different require definition, assessment, and proper documentation; especially as this will determine whether or not Method B testing is needed. This Recommended Practice does not evaluate or quantify other brake system characteristics such as performance, noise, judder, ABS performance, or braking under extreme temperatures or speeds. Minimum performance requirements are not part of this recommended practice. Consistency and margin of pass/fail of the minimum requirements related to wear rates and wear behavior can be assessed as part of the project in coordination with the test requestor. NOTE: This Recommended Practice uses the unit conversion and rounding techniques from the NIST Special Publication 811. This to ensure the use of standard conversion factors and to determine the appropriate number of significant digits to ensure the Rounding Error (RE) of the converted unit is smaller than or similar to the RE of the original English or Imperial unit.
Truck and Bus Hydraulic Brake Committee
Research on Compensation Redundancy Control for Basic Force Boosting Failure of Electro-Booster Brake System2020-01-02164/14/2020
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
Hydraulic Pressure Control and Parameter Optimization of Integrated Electro-Hydraulic Brake System2017-01-25169/17/2017
A general principle scheme of IEHB (Integrated Electro-Hydraulic Brake system) is proposed, and the working principle of the system is simply introduced in this paper. Considering the structure characteristics of the hydraulic control unit of the system, a kind of time-sharing control strategy is adopted to realize the purpose of independent and precise hydraulic pressure regulation of each wheel brake cylinder in various brake conditions of a vehicle. Because of the strong nonlinear and time varying characteristics of the dynamic brake pressure regulation processes of IEHB, its comprehensive brake performance is mainly affected by temperature, humidity, load change, the structure and control parameters of IEHB, and so on. Under certain temperature, humidity and load conditions, whether the matching of the structure and the control parameters of IEHB is appropriate or not, the brake performance of a vehicle would be affected directly and severely, and then the safe driving of a vehicle could not be guaranteed effectively. In order to enhance the adaptability of the pressure regulating performance of IEHB to external influence factors and improve the comprehensive performance index of IEHB, using the software and hardware test platform of IEHB, combining the robustness optimization design method based on the application of GA (Genetic Algorithm) and modern generalized experiments, the structure and the control parameters of IEHB are matched and optimized. Finally, by comparing the results before and after optimization, it is verified that the pressure regulation of optimized IEHB is more rapid, more accurate and more robust, the comprehensive brake performance is significantly improved, and the new type of brake system could well meet the application requirements of an advanced vehicle chassis control system in the future.
Yang, Xiong, Li, Jing, Miao, Hui, Shi, Zheng Tang
Model-Based Pressure Control for an Electro Hydraulic Brake System on RCP Test Environment2016-01-19549/18/2016
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 SystemsJ1707_201609 (Historical)9/13/2016
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
Rubber Boots for Drum-Type Hydraulic Brake Wheel CylindersJ1604_201512 (Current)12/17/2015
This SAE Standard covers molded rubber boots used as end closures on drum-type wheel brake actuating cylinders to prevent the entrance of dirt and moisture, which could cause corrosion and otherwise impair wheel brake operation. The document includes performance tests of brake cylinder boots of both plain and insert types under specified conditions and does not include requirements relating to chemical composition, tensile strength, or elongation of the rubber compound. Further, it does not cover the strength of the adhesion of rubber to the insert material where an insert is used. The rubber material used in these boots is classified as suitable for operation in a temperature range of −40 to +120 °C ± 2 °C (−40 to + 248 °F ± 3.6 °F).
Hydraulic Brake Components Standards Committee
Hardware-in-the-loop Simulation for an Integrated Braking System2015-01-15824/14/2015
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
ASURT Formula Student Brake Design2014-01-24879/28/2014
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
Innovative Concept of Front Disc Brake Module with Weight Reduction and Cost Optimisation2014-01-25059/28/2014
The customer satisfaction index is higher for disc brake systems because of the advantages like less reaction time, shorter stopping distance and improved pedal feel compared to drum brake system. In current competitive market scenario and as per customer requirements, front disc brake module is becoming necessary. The brake system design is challenging task due to stringent performance meeting criteria and packaging constraints with weight optimization. Brake disc is very important component in the brake system which is expected to withstand high braking torque and dissipate heat during braking event. In existing car to replace front drum brake with disc brake module, vehicle needs to undergo legislative verifications and certifications with respect to pedal effort, stopping distance and circuit failed conditions etc. This paper explains development of disc brake system with novel brake disc during transition to switch from drum to disc brake with respect to packaging constraints, which has met all the performance in competitive price. In Conventional disc brake system, brake rotor has hat type construction which is complicated considering design complexity and takes higher manufacturing lead time. Innovative concept of front disc brake (Patented by Tata Motors) with straight brake rotor was evolved and later on designed with respect to packaging constraint. Number of manufacturing steps for this brake disc rotor is drastically reduced, resulted in less manufacturing time with cost & weight reduction. Digital thermal performance evaluated in house, fine-tuned and verified by correlating with test data available for existing design and then applied for new design.
Shah, Ashesh, Patil, Sanjay, Abhyankar, Umesh
Development of Composite Brake Pedal Stroke Simulator for Electro-Hydraulic Braking System2014-01-01174/1/2014
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 Active Control Strategy for Flat Tire Vehicles2014-01-08594/1/2014
This paper first presents an algorithm to detect tire blowout based on wheel speed sensor signals, which either reduces the cost for a TPMS or provides a backup in case it fails, and a tire blowout model considering different tire pressure is also built based on the UniTire model. The vehicle dynamic model uses commercial software CarSim. After detecting tire blowout, the active braking control, based on a 2DOF reference model, determines an optimal correcting yaw moment and the braking forces that slow down and stop the vehicle, based on a linear quadratic regulator. Then the braking force commands are further translated into target pressure command for each wheel cylinder to ensure the target braking forces are generated. Some simulations are conducted to verify the active control strategy. From the simulation results, it is shown that this active brake control strategy can not only ensure the flat tire vehicle stability, but also slow down the vehicle with a safe speed and for a shorter distance.
Liu, Haizhen, Deng, Weiwen, Zong, Changfu, Wu, Jian
Thermomechanical Stress Analysis of Vehicles Gray Cast Brake2013-01-91167/15/2013
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 BrakesJ101_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
Mass Estimation and Axle Load Distribution Algorithm for EBS of Large Bus2013-01-04174/8/2013
The paper describes an algorithm, which estimates the mass of large buses and axle load distribution using pedal position, wheel speed and the wheel cylinder pressure sensors. This algorithm is allowed to achieve the purpose without additional sensors by using the rotational speed sensors from ABS system and air pressure sensors in brake cylinders form ESP system. The axle load distribution algorithm mainly consists of three steps. Firstly, deceleration of the bus is estimated and then the mass of the bus is estimated. After that, the position of the mass centre is estimated. Taking account of the tire nonlinear characteristics under longitudinal forces and vertical forces, mass estimation, deceleration and the position of the mass centre of buses is corrected by the coefficient, which is determined by the wheel cylinder pressure, the wheel speed and mass estimation. When the deceleration, mass of the large bus and the mass center of the whole bus are completely estimated, load of each axle can be obtained through the formula, and also the optimal braking force of each axle for Electronically Controlled Brake System (EBS) can be determined. The comparison between the value of estimation and the value from the Trucksim indicates that: the estimation algorithm is able to achieve accurate value of the mass and axle load of the bus and lays a ground for the development of EBS.
Nie, Zhigen, Zong, Changfu, Wan, Ying
Thermomechanical Stress Analysis of Vehicles Gray Cast Brake2013-01-08774/8/2013
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, Mostefa, Bouchetara
Impact of Pad Wear on the Pressure Dynamics of a Vehicle Braking System2012-01-18979/24/2012
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 ConnectionsJ1290_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
Materials for Plastic Pistons for Hydraulic Disc Brake CylindersJ1568_201204 (Current)4/30/2012
The materials defined by this SAE Standard are glass-fiber-reinforced, mineral-filled phenolic molding compounds suitable for compression molding. Preforms may be radio frequency preheated or screw preheated slugs. Compound for use in hydraulic disc brake caliper pistons.
Hydraulic Brake Components Standards Committee
Shelf Storage of Hydraulic Brake ComponentsJ1825_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
Service Maintenance of SAE J1703 and J1704 Brake Fluids in Motor Vehicle Brake SystemsJ1707_201111 (Historical)11/21/2011
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
Development of New AMT Shift Speed Control System for Lexus LFA2011-28-010310/6/2011
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
Modeling Drivers' Behavior During Panic Braking for Brake Assist Application, Using Neural Networks and Logistic Regression and a Comparison2011-01-23849/18/2011
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
Rubber Cups for Hydraulic Actuating CylindersJ1601_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 Performance2010-01-188510/5/2010
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
Wear of Friction Material during Vehicle Braking2009-01-10324/20/2009
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 Vehicle2009-26-00671/21/2009
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
Repeated Brake Temperature Analysis of Ventilated Brake Disc on the Downhill Road2008-01-257110/12/2008
During braking, the kinetic energy and potential energies of a moving vehicle are converted into the thermal energy through frictional heat between the brake disc and the pads. Most of thermal energy dissipated through the brake disc. The object of the present study is simulation of heating and cooling processes of brake disc to investigate temperature field and temperature variation during driving along a downhill road. The velocity of automobile is limited by repeated brake when the speed exceeds to the maximum limited. The pad-disc brake assembly is built by 3D model and applied appropriate boundary condition. In the simulation process, the mechanical loads are applied to the thermo-mechanical coupling model in order to simulate the process of heat produced by friction. The Analysis results are compared to the measured data obtained from the downhill road brake experiment. The temperature field distribution in the disc under repeated braking presents a non-uniformity characteristic.
Hwang, Pyung, Wu, Xuan, Jeon, YoungBae
Low Water Tolerant Brake FluidsJ1705_200707 (Historical)7/16/2007
This SAE Recommended Practice was prepared by the Motor Vehicle Brake Fluids Subcommittee of the SAE Hydraulic Brake Actuating Systems Committee to provide engineers, designers, and manufacturers of motor vehicles with a set of minimum performance standards in order to assess the suitability of silicone and other low water tolerant type brake fluids (LWTF) for use in motor vehicle brake systems. These fluids are designed for use in braking systems fitted with rubber cups and seals made from natural rubber (NR), 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 existing motor vehicle brake fluids conforming to SAE J1703 and with braking systems designed for such 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 all combinations have not 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
The Freight Train Emergency Brake System and a Method to Calculate Stop Distance and Time2007-01-07214/16/2007
Determining the arrival time for a freight train at a railroad crossing and how the train engineer could affect the arrival is a common question. This paper discusses the freight train brake system, the freight train makeup variables and considerations, and a method to calculate the freight train brake to stop time and distance. The pneumatic brake system, AB brake valve, air propagation rate, braking ratios, braking efficiencies, wheel/shoe adhesions, and the brake system development times are addressed. With the ability to calculate the change in speed, the freight train change in arrival time at a crossing can be determined.
Bentley, John M., Bentley, John
Hydraulic Wheel Cylinders for Automotive Drum BrakesJ101_200608 (Historical)8/16/2006
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
Shelf Storage of Hydraulic Brake ComponentsJ1825_200501 (Historical)1/5/2005
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
High Performance Drum Brake Assembly for Automotive Braking Applications2003-01-330610/19/2003
Different types and sizes of hydraulic drum brake designs viz., two leading sliding shoe, leading-trailing sliding shoe, floating abutment sliding shoe are in existence today catering to the increasing vehicle weight applications. On an end requirement basis and by the cost benefit ratio, either of the above designs with appropriate brake size (diameter) is selected for a given vehicle application. Increasing wheel cylinder size and brake size proportional to the requirement also needs bigger actuation systems and poses packaging constraints within the available wheel sizes. A High performance drum brake assembly is developed from the basic hydraulic, leading-trailing, sliding shoe brake design, which can substantially increase the brake output torque for a given hydraulic input pressure or reduce the required pipeline pressure to realize the current rated torque. The brake assembly has a new lever pivoted on the leading shoe web with one end resting on the wheel cylinder piston and the other end on the strut assembly. This lever touches the piston instead of the leading shoe web and receives input from the pressurized wheel cylinder. Upon actuating the wheel cylinder assembly, the lever rotates about its pivot point and pushes the strut assembly. The trailing shoe now receives two inputs viz., one from the wheel cylinder and the other from the strut assembly, which is mechanically actuated by the new lever. The reaction from the trailing shoe is passed via the strut assembly as an input to the leading shoe. The wheel cylinder input and the strut reaction force together acting on the pivot, results in almost twice the force acting on the leading shoe. Prototype samples incorporating the new design is developed and validated on inertia dynamometer.
Raajha, M. P., Narayanan, V. Lakshmi
Hydraulic Design Considerations for EHB Systems2003-01-03243/3/2003
Brake performance can be divided into two distinct classes: base brake performance and controlled brake performance. A base brake event can be described as a normal or typical stop in which the driver maintains the vehicle in its intended direction at a controlled deceleration level that does not closely approach wheel lock. All other braking events where additional intervention may be necessary, such as wheel brake pressure control to prevent lock-up, application of a wheel brake to transfer torque across an open differential, or application of an induced torque to one or two selected wheels to correct an under- or oversteering condition, may be classified as controlled brake performance. Statistics from the field indicate the majority of braking events stem from base brake applications and as such can be classified as the single most important function. From this perspective, it can be of interest to compare modern-day Electro-Hydraulic Brake (EHB) hydraulic systems with a conventional vacuum-boosted brake apply system and note the various design options used to achieve performance and reliability objectives.
Reuter, David F., Lloyd, E. Wayne, Zehnder, James W., Elliott, Joseph A.
Influence of Friction Law on Brake Creep-Groan2001-01-313810/28/2001
Brecht, J., Schiffner, K.
The Kinetic Brake Booster2001-01-318910/1/2001
Main defect of traditional structure of the brake boosters is the necessity of an external energy source. The analysis of redistribution of power streams occurring during at braking of the automobile shows that it is possible to use the force component of the driving automobile kinetic energy for the drive of a booster (so-called kinetic booster). The power consumed by a booster is taken from power developed during brake action thereby it promotes vehicle slowing down. In the paper for the booster work the schemas of power take-off from an engine, onboard electric system, transmission, single wheel are considered. Especially for brake-by-wire systems the project of pilot management is probed. It allows applying the serial x-by-wire components both on small automobiles andon vehicle with the great load-carrying capacity and trailers.
Ivanov, Valentin, Lepeshko, Joseph, Boutylin, Vladimir
Materials for Plastic Pistons for Hydraulic Disc Brake CylindersJ1568_200105 (Historical)5/14/2001
The materials defined by this SAE Standard are glass-fiber-reinforced, mineral-filled phenolic molding compounds suitable for compression molding. Preforms may be radio frequency preheated or screw preheated slugs. Compound for use in hydraulic disc brake caliper pistons.
Hydraulic Brake Components Standards Committee
A development of electronic load sensing proportioning valve for control of brake pressure using direct adaptive fuzzy algoirthm2000-05-02666/12/2000
In the brake system a proportioning valve which reduces the brake pressure at each wheel cylinder for anti-locking of rear wheels is closely related with the safety of vehicles. But, it is impossible for a present proportioning valve to exactly control brake pressure because mechanically it is an open-loop control system. So, in this paper, we describe an electronic brake pressure distribution system using a direct adaptive fuzzy controller in order to exactly control brake pressure using a closed-loop control system. The object of electronic brake pressure distribution system is to change a cut-in pressure and a valve slop of proportioning valve in order to have better performance of brake system more than that of the previous systems.
Kim, Hunmo, Kim, Seungdae, Ki, Namheon
Brake System with Double Link-Type Variable Ratio Brake Pedal2000-01-04383/6/2000
In the past, in order to have good brake effectiveness, it was necessary to adopt high coefficient friction materials for pads or linings, or enlarged brake effective radii. But high coefficient material can create problems such as noise or vibration. And increasing effective radii is limited by the wheel package. A high pedal ratio can provide good effectiveness, but also leads to long pedal travel and poor brake feel. Specifically for trucks and SUV's with large GVW's, it can be difficult to achieve both good brake effectiveness and good pedal feel. In response to this difficult design challenge, a double link-type variable ratio pedal was developed for a production application.
Yabusaki, Naoki, Shimizu, Hidetoshi, Sakamoto, Shigeru, Isono, Hiroshi
The Development of a Temperature Alarm Device for Failure Prevention of the Automobile Hydraulic Brake System1999-01-04743/1/1999
The pursuit of safer and more reliable car is the trend of modern automobile engineering. The major protection against an automobile accident is the brake system. However, to date, there is no safety device, which is designed to prevent failure from high temperature of the hydraulic brake system. In general, the brake force is generated from the friction between brake shoes and brake drums or disks. As the vehicle slows down, the moment of inertia of the vehicle is transformed into heat to raise the temperature of the brake system. The rapid rising of temperature may result in serious safety concerns of the brake system and its failure could be expected. The main purpose of this research is to develop a device, which can detect high temperature in the hydraulic brake system and provide a safety alarm before it fails. The device utilizes temperature sensors to monitor temperatures of the brake shoe lining and hydraulic fluid of the brake wheel cylinders. Both of the current temperatures are checked with alarm control parameters. When either one of the temperatures exceed the preset value, the control unit will send an alarm signal to warn the driver who should then take precaution and/or prevention actions
Lee, Shuo-Jen, Lin, Ke-Feng, Tai, Chi-Fu, Wu, Shih-Hsiung, Gau, Chung-Yun
Shelf Storage of Hydraulic Brake ComponentsJ1825_199801 (Historical)1/1/1998
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
Analysis of Water Content in Brake Fluid. Part I. Method Comparison: Karl Fisher Titration Versus Refractive Index97302310/6/1997
The water content of hydraulic brake fluid affects boiling point, viscosity and the corrosive nature of the fluid. Brake overheating can boil fluids containing a significant amounts of water, causing loss of brake function. High water content can also corrode system components. A quick, easy method for determining water in brake fluid would enable service technicians to recommend brake fluid changes before either safety or corrosion concerns arise. This study compares the refractive indices and water content of a sample of new commercial DOT 3 and DOT 4 brake fluids. Measurements were made with 0 to 7% water added to the brake fluids. Added water content is compared to water content as determined by Karl Fisher titration. The 589nm refractive index of samples was measured at two temperatures to assess temperature sensitivity. Measuring refractive index to a high degree of accuracy is fairly easy. The measurements take less than 1 minute each. They do not require use of reagents or volume-weight measurements. This study shows there is little change in absolute index for a wide range of brake fluids. A very significant change in refractive index occurs as water is added to samples. DOT 3, high boiling point DOT 3 and DOT 4 Fluids showed very little difference in absolute refractive index and identical changes in refractive index due to added water.
Ryan, Thomas E., Hinz, Todd
Improved Methods for Testing the Durability of Corrosion Protection in Brake Fluids9710072/24/1997
Present corrosion testing procedures for brake fluids assess the properties of fresh fluids under some forms of environmental stress (e.g., water content, elevated temperature). These tests may not accurately predict corrosion protection properties of fluid after the years of continuous service typical of North American practice. This paper describes the development of laboratory accelerated aging procedures which reproduce the chemical changes occurring in brake fluids during long-term service. Short-duration vehicular tests with these lab-aged fluids have reproduced specific modes of corrosion previously observed only after long-term customer use.
Jackson, Garry L., Lévesque, Pierre, Wagner, Frederick T.
Rubber Seals for Hydraulic Disc Brake CylindersJ1603_199501 (Historical)1/10/1995
This SAE Standard describes the performance and part requirements for elastomeric seals used in highway vehicle disc brake calipers. Seals covered by this specification may be the solid section type (square, rectangular, O-ring, etc.) mounted stationary in the cylinder bore or on the movable piston.
Automotive Brake and Steering Hose Standards Comm
Development of a Test Rig for Evaluation of a Motorcycle Disc Brake Performance93201611/1/1993
Experiment has been conducted to investigate the performance of a motorcycle disc brake. The primary purpose of the investigation is to observe the capacity of the disc brake in absorbing energy during braking. It can be measured by determining the deceleration during braking. The normal disc brake should comply with the regulation stated by the Department of Communication that it has to achieve a deceleration of minimum 0.25 g during maximum braking. In this paper, the main emphasize is given to the development of a test rig that can perform brake test and that it can be used for any other brake testing and for practical use. The test rig can simulate the actual inertia during braking on the road. The rotation of the disc can be adjusted so that it matches the normal operating speed of the motorcycle. The test rig is also equipped with the pressure controller to adjust the amount of force needed to hold the disc tightly. Brake evaluation is done by providing the necessary inertia and by providing brake pressure at certain speed. The inertia can be adjusted by changing the rotation of the flywheel, the brake pressure can be adjusted through a hydraulic cylinder.
Soemantri, Satryo, Natih, IGP
New Generation Clutch Hydraulic Actuation System9309103/1/1993
Traditionally manual clutch actuation for automobiles was a spinoff from hydraulic brake technology namely heavy steel or cast iron cylinders, steel pipes and rubber hoses. Because of this archaic, inefficient and expensive approach to providing a mechanical advantage, an alternative lower cost system of cable operation gained popularity throughout the industry. However, the 1:1 ratio of a cable plus routing problems, NVH issues, efficiency losses and the need for complex adjustment mechanisms, opened up the opportunity for a rebirth of the old hydraulic concept. The goal was to design a system with a totally new approach that would meet the following criteria: High efficiency, increased temperature resistance, increased durability, reduced package size and weight, cost competitive with cable systems, and finally to take advantage of the latest advances in materials and processes. This paper will describe the “New Generation Clutch Hydraulic Actuation System” (see Figure 1) from initial concepts, through to the full production stage and acceptance in the automobile industry.
Leigh-Monstevens, Keith V., Branum, Leslie P., Strbik, Christine A., Regula, Paul M.
Bus Fires: Cause Determination and Recommendations92245611/1/1992
Over a year's period I investigated fires in six large (about 70 passengers) city transit buses and a 19-passenger bus/van equipped with a wheelchair lift. In all cases there were no injuries or deaths, but this was mainly a result of luck and lightly-loaded buses-there could just as easily have been multiple injuries or fatalities in each case. The causes were multiple-electrical, burst radiator hose, etc. But what I discovered was that whereas most fires originated in the engine compartments and effectively destroyed the engines, it was “other factors” which caused the fire to spread and destroy the entire vehicle. With proper attention to the “other factors,” the loss of a $200,000 bus could be averted and damage limited to the engine, at perhaps one-tenth the cost and with no risk to human life. These “other factors” will be discussed. Buses contain a number of unique hazards. Often, they have a people-density much greater than would be allowed in a building by fire codes. They may be moving at speeds of 70 m.p.h. (or more!). The exits are often inadequate. There is the possibility of riders in wheelchairs, who would be nearest the front door. In the event of a fire, getting the wheelchair-bound passengers or passengers off first would delay getting the other passengers off.
Carleton, Joseph
The Effect of Brake System Evacuation and Fill on Initial Brake Pedal Travel9105742/1/1991
The effectiveness of a brake system evacuation and fill will be shown to be quantifiable in terms of initial brake pedal travel by way of a few simple hand calculations. This paper does not discuss the mechanics of evacuation and fill, rather, it is a study into the impact of the evacuation and fill process upon initial brake pedal travel. First, initial pedal travel due to the evacuation and fill process will be quantified by a series of calculations. Secondly, empirical data will be presented which will demonstrate the close correlation of calculated results to those obtained in actual brake system tests.
Clark, Neil J.
Rubber Seals for Hydraulic Disc Brake CylindersJ1603_199006 (Historical)6/1/1990
This SAE Standard describes the performance and part requirements for elastomeric seals used in highway vehicle disc brake calipers. Seals covered by this specification may be the solid section type (square, rectangular, O-ring, etc.) mounted stationary in the cylinder bore or on the movable piston. The specification contains the following major sections:
Hydraulic Brake Components Standards Committee
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