Browse Topic: Brake cylinders

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Coordinated Control of DYC/ABS for Cornering Braking Based on Driver Intention2025-01-734012/31/2025
This paper proposes a DYC/ABS coordinated control strategy for cornering and braking based on driver intention. A hierarchical control structure is established, where the upper-level controller uses a vehicle dynamics model to calculate the additional yaw moment required by the DYC controller to track the desired yaw rate and sideslip angle, as well as the driver’s intended braking intensity. Taking multiple constraints into account, a quadratic programming algorithm is employed to optimize the distribution of braking forces among the four wheels. The lower-level ABS controller is designed with multiple thresholds and corresponding control phases to precisely regulate the hydraulic pressure of individual wheel cylinders. In emergency braking scenarios where ABS intervention may conflict with the upper-layer braking force allocation, a rule-based, stepwise diagonal pressure reduction compensation strategy is proposed. This strategy fully considers the influence of longitudinal and lateral forces of each wheel on the vehicle's yaw moment. By selectively reducing brake pressure, it generates an additional yaw moment to compensate for the negative impact of ABS on vehicle steerability, while ensuring a smooth pressure transition. The proposed strategy is validated on a Driver-in-the-Loop (DIL) simulation platform built using NI PXI, DSPACE, and external driver inputs such as the steering wheel and brake pedal. Under various driver braking intentions and cornering scenarios with high and low road adhesion, the strategy shows significant improvements in fulfilling driver braking demands and enhancing vehicle yaw stability compared to the non-optimized strategy.
Zou, Yan, Ma, Yao, Kong, Yan, Pei, Xiaofei
Development of an Imperceptible Brake Failure Control Technology and Real Vehicle Application10-09-02-00154/26/2025
With the advancement of control technology in the automotive field, there is a possibility of cross-system redundant control between various actuators. As for the braking system, current brake-by-wire system often uses mechanical backup braking methods to give the vehicle a certain braking capacity after failure. However, in the mechanical backup braking mode, the brake master cylinder is connected to the supporting wheel cylinder, and the brake assist is lost, which leads to an increase in brake pressure and makes it difficult for the driver to step on the brake pedal. Meanwhile, due to the limitation of the brake master cylinder stroke, the maximum braking deceleration of the vehicle is only 3 m/s2 after the driver fully presses the brake pedal. The above two defects greatly affect the safety of the vehicle during backup braking. To solve the above problems, this article takes electric vehicles as the research object, designs a new type of hydraulic circuit for the braking system, and develops a backup braking method that integrates the drive motor and electronic parking system. This article builds a vehicle simulation model and selects real vehicles for actual testing. The results showed that in backup braking mode, the driver obtained the braking sensation during normal braking, and the maximum braking deceleration of the vehicle reached 10 m/s2. Overall, the backup braking method designed in this article effectively solves the drawbacks of the current brake-by-wire system and improves the safety of vehicles during backup braking.
Tian, Boshi, Li, Liang, Liao, Yinsheng, Lv, Haijun, Hu, Zhiming, Sun, Yue, Qu, Wenying
Research on Pressure Control Methods for a Dual-Source Electro-Hydraulic Brake System with Redundant Braking Function2025-01-87164/1/2025
This paper presents a novel Dual-source Electro-Hydraulic Brake system (D-EHB) that incorporates a redundant braking module to enhance safety and reliability. The D-EHB is designed to address the critical issue of brake failure in vehicles, which can lead to severe accidents. The D-EHB system comprises two independent units: the Main Brake Unit (MBU) and the Redundant Brake Unit (RBU). Each unit has its own hydraulic power source. The MBU's hydraulic pressure is generated by a combination of a servo motor, ball screw, and servo piston, while the RBU has a simpler structure, with hydraulic pressure generated by a motor and plunger pump combination. Mathematical models for each component of the D-EHB have been developed and validated using AMESim. The mathematical models of each part were then combined to design a wheel cylinder hydraulic pressure estimation algorithm that can calculate the wheel cylinder pressure based on motor and valve output signals, making the system applicable to vehicles without pressure sensors in the wheel cylinders. Given the distinct characteristics of the MBU and RBU, different pressure control methods were proposed. The MBU control leverages the P-V characteristics of the servo cylinder and employs Sliding Mode Control (SMC), with the target position of the servo cylinder piston as the control output, ensuring that the hydraulic pressure of the servo cylinder quickly and accurately reaches the desired value, while maintaining robust performance. The RBU control is based on the overflow characteristics of the solenoid valve and uses proportional control. Simulations and bench tests were conducted to compare the pressure control performance of the RBU with that of the MBU. The results demonstrate that the MBU exhibits excellent control accuracy and response speed, while the RBU, although not as precise as the MBU, still meets the braking requirements.
Wang, Wenqiang, Zhao, Xuezhi, Shangguan, Wen-Bin, Ren, Bingyu
Evaluation and Prevention of Brake Drum Freezing by Aerodynamic Measures2025-01-87754/1/2025
The use of drum brakes in Battery Electric Vehicles (BEVs) offers numerous benefits, including energy efficiency, reduced brake dust emissions, and reliable performance under challenging weather conditions. The capability of regenerative braking reduces the friction brake application frequency in BEVs and therefore the brakes can be prone to corrosion and performance degradation especially considering conventional disc brake systems. The closed design of a drum brake prevents corrosion of the friction-components by sealing out water, dirt or snow. A common sealing concept is performed with a labyrinth between the gap of the rotating drum and the axle mounted backplate. A hermetical isolation of water and snow ingress into the drum cannot be achieved with this concept, so additional aerodynamic measures are necessary to deflect the air/water path and protect the inner brake components. Additionally, interfaces like wheel cylinders, electric park brake parts, brake shoe pins, and axle mountings can potentially lead to leaks on the backplate. This study highlights the impact of water/snow ingress on the example of a frozen parking brake during cold climate on-road testing. Through scientific investigation using the state-of-the-art fluorescence method, drum leakages were visualized, and the extent of water ingress was measured. Multiple multiphase CFD simulations supported the design phase of the aerodynamic measures. Subsequently, the vehicle was cooled down to -10 °C to simulate the cold climate test conditions. The frozen parking brake situation could be reproduced with this method, and beneficial aerodynamic and sealing measures were extrapolated to avoid the drum brake from freezing. The tests were conducted in the FKFS Thermal Wind Tunnel, a wind tunnel comprising a two-axle-dynamometer and water irrigation systems with UV illumination.
Hennicke, Tim, Kuthada, Timo, Bernhard, Adrian, Reichhart, Leander, Weber, Eugen, Moers, Michael, Rettig, Marc
Torque Vectoring for Lane-Changing Control during Steering Failures in Autonomous Commercial Vehicles2024-01-23284/9/2024
Lane changing is an essential action in commercial vehicles to prevent collisions. However, steering system malfunctions significantly escalate the risk of head-on collisions. With the advancement of intelligent chassis control technologies, some autonomous commercial vehicles are now equipped with a four-wheel independent braking system. This article develops a lane-changing control strategy during steering failures using torque vectoring through brake allocation. The boundaries of lane-changing capabilities under different speeds via brake allocation are also investigated, offering valuable insights for driving safety during emergency evasions when the steering system fails. Firstly, a dual-track vehicle dynamics model is established, considering the non-linearity of the tires. A quintic polynomial approach is employed for lane-changing trajectory planning. Secondly, a hierarchical controller is designed. The upper layer employs a three-stage cascaded proportional integral controller to determine the total yaw moment required for lane changing, considering the influence of lateral tire forces on brake allocation. The middle layer uses constraint optimization to manage braking force distribution among the four wheels. The lower layer's actuator generates brake torque through brake cylinder pressurization. Finally, the effectiveness and feasibility of the control strategy are validated using joint simulations on Matlab/Simulink and Trucksim over diverse longitudinal distances. Simulation results indicate that autonomous commercial vehicles can execute swift and safe lane changes at varying speeds during steering failures.
Lu, Ao, Li, Runfeng, Yinggang, Xu, Nie, Zexin, Li, Peilin, Tian, Guangyu
Sensorless Control of a Brushless Motor for the ESC Unit2023-01-04524/11/2023
In general, automatic braking uses an electric stability control (ESC) hydraulic unit that can automatically increase the hydraulic pressure in the wheel cylinder (hereinafter called wheel pressure), independent of the driver’s braking operation. The hydraulic unit should have sufficient pressure response to apply autonomous emergency braking (AEB). It was necessary for the hydraulic unit to have a high flow rate for the pressure response. To satisfy the performance requirements of the AEB, a brushless motor, which has a high maximum rotational speed and good response, is adopted for the hydraulic unit. Furthermore, sensorless control, which does not require a rotation angle sensor, has been developed so that the motor size can be small and common to conventional units. The developed sensorless control can switch the driving methods in three states: pre-rotation, low speed, and high speed. In the pre-rotational state, the magnetic poles are judged to quickly determine the initial position of the motor rotor. The rotational speed in the low-speed range was estimated based on the disturbance superimposition method. Subsequently, the rotational speed in the high-speed range was estimated based on the extended guidance method. The sensorless control can drive the brushless motor with the same performance as that of a system equipped with a rotation angle sensor over a wide range of rotational speeds. A sensorless control system that has the same performance as a system equipped with a rotation angle sensor was developed, which allows the miniaturization of the motor.
Kawamura, Hikaru, Kokubo, Koichi, Naito, Masayuki, Iida, Takanori, Takahashi, Atsushi, Takahashi, Tomoya
Research on Thermal Recession Compensation Method of Disc Brakes2023-01-06684/11/2023
If a car is braked frequently or at high speed, the thermal decay of brake system performance appears, which reduces the braking performance of the car. To compensate brake moment reduction during braking at thermal decay of brake system, a compensation strategy of brake moment is designed by using “feedforward +PID feedback” to pressure at wheel braking cylinder. The trigger and exit conditions of the strategy for the wheel cylinder pressure are proposed based on the threshold. A vehicle model consisting braking system is established if a vehicle runs at straight line, and the braking distance and braking acceleration are estimated, the results shown that the thermal decay compensation control strategy proposed in this paper can reduce the braking distance and braking time. A braking system experiment if a car runs at straight line is carried out, it demonstrates that if temperature of a disc brake is higher than 300°C, the thermal decay will occur, and friction coefficient decreases by 16.7% compared with the nominal friction coefficient. Brake thermal decay compensation strategy proposed in this paper can enhance braking safety performance if thermal decay happens.
Tan, Zhi-Fang, Kang, Yingzi, Shangguan, Wenbin, Wang, Weiwei, Jiang, Kaihong
A Comparison Study on Control Strategies for Optimization of an Anti-Lock Brake System Algorithm Based on Tire Force Measurement in Pure and Combined Slip Conditions of an Automobile2023-01-06944/11/2023
The Anti-Lock Braking System (ABS) is a safety critical feature primarily used to control slipping of wheels, to maximize available traction and minimize stopping distance. Regulatory authorities of many countries have mandated implementation of an ABS as a compulsory safety feature to be present in all road legal automobiles. Hence, apart from avoiding wheel lock-up, an ABS must also ensure that the vehicle maintains its handling stability and steerability while braking. Thus, it is important that the ABS controller modulate and apply adequate amount of brake cylinder pressure. This paper suggests the use of a Tire Force based algorithm to analyze vehicle behavior and accordingly a control law is employed to modulate the wheel brake pressure. A comparison study has been performed among control methods such as Step Gain Reduced Order Model (SGROM) developed using Machine Learning techniques and Linear Quadratic Regulator (LQR) to determine an optimal control law for brake pressure modulation under pure and combined slip condition. The SGROM control technique implements a wheel cylinder pressure gain that is a function of vehicle state variables such as input brake pressure, normalized tire force and vehicle speed. The optimum output pressure gain is estimated by using a machine learning technique that is further elaborated in the paper. The LQR control technique regulates wheel cylinder pressure gains by minimizing cost function based on desired braking characteristics. The control algorithms are evaluated based on standard brake performance tests such as stopping distance, split mu, and brake in turn. Accordingly, an optimal control strategy is selected based on evaluation criteria defined in the standards.
Shaikh, Parvez Shagir, Mehta, Harshal Piyush, Mallikarjunaiah, Umesh, Kamble, Vijay, Maurya, Mithilesh
Inertia Dynamometer Brake Squeal Noise Test Procedure for Vehicles without Regenerative SystemsJ2521_202210 (Current)10/7/2022
The SAE J2521 procedure applies to high-frequency squeal noise occurrences for on-road passenger cars and light trucks below 4540 kg of GVWR. The procedure incorporates high-temperature and low-temperature test matrixes but does not fully account for the effects of the environment on brake squeal. For this test procedure, squeal occurs when the peak noise level is at least 70 dB(A) between 1.25 kHz and 16 kHz for tests using full suspension corners or full axle assemblies or between 2 kHz and 16 kHz for brakes not using a full suspension corner. Before using this recommended practice for chassis dynamometer testing, review in detail the specifics related to at least (a) instrumentation, including in-cabin microphones, (b) threshold levels for noise detection, (c) temperature control priority between the front and rear axles, (d) vehicle loading and load distribution, (e) cooling air and environmental conditioning, and (f) detailed nomenclature and labeling of channels and sensors.
Brake NVH Standards Committee
Research on Vehicle Rollover Warning and Braking Control System Based on Secondary Predictive Zero-Moment Point Position2022-01-09163/29/2022
To solve the contradiction between model complexity and the warning accuracy of the algorithm of the vehicle rollover warning, a rollover state warning method based on the secondary predictive zero-moment point position for vehicles is proposed herein. Taking a sport utility vehicle(SUV) as the research object, a linear three-degrees-of-freedom vehicle rollover dynamics model is established. On the basis of the model, the lateral position of the zero-moment point and its primary and secondary rates of change are calculated. Then, the theoretical solution of time-to-rollover of the vehicles is deduced from the lateral position of the secondary predictive zero-moment point. When the rollover warning index, the lateral position of the zero-moment point, is greater than the set threshold, the active anti-rollover control system will be triggered. The active anti-rollover braking control system adopts a hierarchical control strategy. Taking the rollover warning index as the control target, the upper controller calculates the braking torque required by the front-outer wheel based on the Fuzzy Proportional Integral Derivative (PID) algorithm and the differential braking control strategy. The lower executive controller calculates the corresponding brake wheel cylinder pressure and inputs it to the corresponding wheel through the Electrical Hydraulic Brake(EHB), so that a certain additional yaw moment can be formed to prevent the vehicle from rolling over. Under some typical driving conditions, Carsim-Matlab co-simulation and real vehicle tests are carried out. The comparative test results show that the proposed rollover warning method based on the secondary predictive zero-moment point position can accurately and effectively predict the roll-over state of the vehicle, and the active anti-rollover braking control system can control the vehicle in time and effectively to prevent the vehicle from rollover.
Wang, Haiyang, Hou, Liming, Shangguan, Wen-Bin
Active Brake Wheel Cylinder Pressure Control Based On Integrated Electro-Hydraulic Brake System2022-01-02933/29/2022
With the development of the automobile industry, the requirements of quick response and high performance are put forward for the brake system. Since the traditional brake system cannot achieve these, the international brake parts manufacturers put forward an integrated electro-hydraulic brake system -the 1-Box. It can realize active brake through the servo motor. In addition, by controlling the pressure of the servo cylinder and working with solenoid valves, the wheel cylinder pressure can be controlled. However, it has some problems, such as hydraulic hysteresis disturbance and complex friction obstruction, which cause obstacles to the accurate control of wheel cylinder pressure. In this paper, the active braking pressure control strategy of wheel cylinders is designed based on 1-Box. First, introduce the configuration and the working principle of wheel cylinder pressure control; Next, design the servo cylinder active braking pressure control strategy composed of servo loop and pressure loop. The servo loop has completed the closed loop of the servo position control, which overcomes complicated friction configurations. The pressure loop consists of a feedforward controller and a closed-loop feedback controller to overcome the problems of hydraulic hysteresis; Then, the rate of pressure increase/reduction of inlet and outlet valves is calibrated based on the hardware-in-the-loop test bench. And a combined control strategy of wheel cylinder pressure is designed, which can realize single wheel pressure regulation and multi-wheel pressure regulation. Finally, the algorithm is tested by hardware-in-the-loop test bench. The results show that the wheel cylinder pressure control strategy designed in this paper can achieve good wheel cylinder pressure control effect of 1-Box.
Zhang, Jian, Li, Linrun, Jiang, Hongwei, Liu, Qiuzheng, Wang, Yu, Yuan, Wenjian, Wu, Jian, Zhang, Xuhan, Chen, Zhicheng
Guidelines for Developing and Revising SAE Nomenclature and DefinitionsJ1115_202107 (Current)7/23/2021
Vehicle E E System Diagnostic Standards Committee
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
A Passenger Car Brake Pedal Feel Analysis Model Based on Integrated Brake by Wire System2021-01-09754/6/2021
The fully decoupled brake by wire system is a complex system consisting of mechanical components such as springs and rubber and hydraulic structural components coupled together. Compared to conventional braking systems, it is characterized by the full decoupling of the brake pedal from the brake wheel cylinders in normal braking mode, and the pressure fluctuations in the wheel cylinders do not affect the pedal feel. In order to predict brake pedal feel in a passenger car, a dynamic model was developed for both normal and backup braking modes, taking into account the variation of the volume modulus of the brake fluid and the frictional forces of the master cylinder pistons. The influence of different pedal input speeds on the pedal feel characteristic curve was analyzed using static vehicle tests and the related parameters of the braking system were identified in order to correct the design data. Subsequently, a dynamic test of the vehicle pedal feel was conducted to establish a quadratic graph of pedal stroke, pedal force, servo cylinder pressure and vehicle longitudinal deceleration. The accuracy of the dynamics model was verified using vehicle tests, and we believe that this new dynamics model of the decoupled brake system can accurately predict brake pedal feel and can be used for the design and optimization of the brake system.
Yin, Faguo, Wang, Minghui, Jiang, Yongfeng, Kang, Yingzi
A Component Level Test Methodology to Validate Hydraulic Clutch Slave Cylinder2021-01-07094/6/2021
In this current fast-paced world, releasing a defect free product on time is of utmost importance in the automotive domain. The automobile powertrain is designed with a fine balance of weight and power. Clutch, an intermediate part between engine & transmission in manual transmission vehicle plays crucial role for vehicle smooth drive & functionality. Hydraulic clutch slave cylinder (CSC) which is a part of clutch release system was observed with one failure mode in one of the vehicles during internal road validation. It facilitates to actuate the clutch diaphragm in order to disengage the clutch when clutch pedal is pressed and to re-engage the clutch back when the clutch pedal is released. CSC failure directly disconnects the response of leg to clutch and thus driver may lose vehicle control and can possibly cause a severe vehicle crash. After investigation and dismantling the failed part, wear marks were observed on anti-rotation pin (which locks CSC hydraulic chamber against plastic body) and on elliptical O-ring, which locks oil flow to the plastic chamber. Unique in the industry, a component-level test setup was developed for validation and improved CSC design. Few samples were successfully tested for failure simulation and results were very encouraging. For strengthening of the CSC, design modification was done, and the new designed parts were tested on the same component-level test setup for validation. The sample passed the component-level test, and subsequently vehicle level test, and was approved for production. The component-level test methodology helped to test multiple design iterations and samples within a postulated time and cost. This methodology can be used as a part of front-loading support for all future projects.
Kathrecha, Devanshu, Chakraborty, Abhirup, Sebastian, Jobin, Jha, Bhaskar, M, Sudhan
Disc and Drum Brake Dynamometer Low-Frequency Noise Test ProcedureJ3002_202101 (Current)1/27/2021
This test procedure outlines the necessary test equipment (test fixture, dynamometer, data acquisition system, etc.) and test sequence required to test for low-frequency brake noise (200 Hz to 1.25 kHz) on a brake noise dynamometer. It is intended to complement SAE J2521, which focuses on high-frequency brake squeal. This RP applies to passenger cars and light trucks with a gross vehicle weight rating below 4536 kg. Before using this RP for heavier vehicles, consult and agree with the test requestor and the testing facility.
Brake NVH Standards Committee
Snowmobile Brake Control SystemsJ1282_202101 (Current)1/27/2021
This SAE Standard establishes a uniform testing procedure and performance requirements for a snowmobile brake control systems.
Snowmobile Technical Committee
Low-Duty Inertia Dynamometer Hydraulic Brake Wear Test Procedures for Vehicles Above 4536 kg (10000 pounds) of GVWRJ3006_202005 (Historical)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 Control Target of Truck Platoon Based on Maximizing Fuel Saving Rate10-04-02-00102/4/2020
In view of the inability of traditional constant spacing policy to maximize the fuel saving rate of the truck platoon when choosing the smaller desired vehicle spacing as the control target, a new control strategy is proposed in this article. This strategy dramatically reduces the fuel consumption of the truck platoon from the start to the formation of a stable platoon, thus greatly increasing the fuel saving rate of the platoon. To prove the effectiveness of the strategy, this article carried out the longitudinal dynamics modeling of the truck and the modeling of the fuel consumption model of engine first. Longitudinal dynamics modeling establishes the dynamic equations for truck braking and nonbraking. The fuel consumption model of engine is built using a three-dimensional map. Second, the design of the controller is described. The controller calculates the desired acceleration of the following vehicle based on the speed error and the following distance error. The longitudinal dynamic equation of the truck is used to derive the desired engine torque or the desired braking torque of the following vehicle, which realizing the decision of the throttle opening and the wheel cylinder pressure of the following vehicle according to actual conditions. The software simulation is carried out in the end. The simulation results show that the new control strategy is more fuel efficient than the traditional CSP.
Zheng, Hongyu, Wu, Jianjun, Pan, Kaiqiang, Meng, Wanjia, Li, Rui
Snowmobile Brake Control SystemsJ1282_201902 (Historical)2/27/2019
This SAE Recommended Practice is intended to provide the minimum acceptable criteria for snowmobile hand brake control systems. This recommendation is not intended to cover competition vehicles, nor is it intended to limit development of new and/or improved technology in controls. Although these recommendations are primarily addressed to hand control systems using an outer flexible conduit with a multiple strand inner cable or hydraulic type brake control system, the basic requirements of freedom of movement, strength, material, etc., will apply to any system.
Snowmobile Technical Committee
A Braking Force Distribution Strategy in Integrated Braking System Based on Wear Control and Hitch Force Control2018-01-08274/3/2018
A braking force distribution strategy in integrated braking system composed of the main braking system and the auxiliary braking system based on braking pad wear control and hitch force control under non-emergency braking condition is proposed based on the Electronically Controlled Braking System (EBS) to reduce the difference in braking pad wear between different axles and to decrease hitch force between tractors and trailers. The proposed strategy distributes the braking force based on the desired braking intensity, the degree of the braking pad wear and the limits of certain braking regulations to solve the coupling problems between braking safety, economical efficiency of braking and the comfort of drivers. Computer co-simulations of the proposed strategy are performed. The braking force distribution strategy is verified under condition of equal wear of braking pad, condition of greater wear on the front axle of tractor and condition of greater wear on the rear axle of the tractor. The simulation results show that the proposed strategy balanced the braking pad wear by regulating the braking cylinder pressure of each axle and ensured the same braking distance under different wear conditions of braking pad. Under unloaded or loaded conditions, each axle braked according to the desired braking intensity and reached the control objective that the same braking pedal opening rate is in accord with the same braking intensity. Under different load conditions, the strategy ensured the same braking distance and reduced the hitch force, which definitely enhanced the braking safety, economical efficiency of braking and the comfort of drivers.
Zheng, Hongyu, Liu, Chen, Wang, Linlin
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
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
Mechanical Systems Physics-of-Failure Analysis Experimental ValidationJ2869_201608 (Current)8/4/2016
This report details continuing work examining the fatigue life durability of a US Army Trailer. This report describes, through example, a process to evaluate and reduce the experimental data needed for a Mechanical Systems Physics-of-Failure analysis. In addition the report describes the process used to validate the computer simulation models.
G-41 Reliability
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
RISE OF THE UNDERDOGS15MEIP06_036/1/2015
Problem-plagued effort last year spurs Baja SAE team from VIT University of India to overhaul itself and its car. This article isn't a thrilling discourse about engineering innovation and game-changing technology. It most definitely isn't a dramatic rags to riches story. Neither is it a satirical piece on the often erroneous experiments that make Baja SAE a fantastic platform for students to learn and thrive in the automotive industry. Rather, this story is the firsthand account of how a Baja SAE team from India with international ambitions is turning its fortunes around through a complete perspective change, calculated risk-taking and, of course, a touch of luck.
RISE OF THE UNDERDOGS15MOMP04_024/1/2015
Problem-plagued effort last year spurs Baja SAE team from VIT University of India to overhaul itself and its car. THIS ARTICLE ISN'T A THRILLING DISCOURSE ABOUT ENGINEERING INNOVATION and game-changing technology. It most definitely isn't a dramatic rags to riches story. Neither is it a satirical piece on the often erroneous experiments that make Baja SAE a fantastic platform for students to learn and thrive in the automotive industry. Rather, this story is the firsthand account of how a Baja SAE team from India with international ambitions is turning its fortunes around through a complete perspective change, calculated risk-taking and, of course, a touch of luck.
Laser Surface Hardening of Ductile Irons2014-28-00214/28/2014
Desired mechanical properties including wear resistance at affordable price are the key parameters for which ductile cast irons are widely selected. Particularly, in many automobile applications like brake cylinders, camshafts, connecting rods, gears, pistons and yokes ductile iron is used. Traditionally surface heat treatments like induction hardening and in recent times electron beam and laser hardening are used to improve wear and fatigue resistance of ductile irons. However, the laser surface hardening has a lot of advantages over others such as low distortion due to high power density, flexibility, accuracy, lack of quenching medium and limited grain growth. In this work, laser surface hardening of Ferrito pearlitic ductile iron grade has been carried out. Hardening was performed with a 400W continuous wave fiber laser with the objective to investigate the effect of local tempering in continuous laser multi-pass laser surface hardening on hardness profile of the specimen. Experiments were conducted by varying four process parameters namely power density, scanning speed, scan length and beam overlap. These process parameters were optimized. Surface characterizations of laser hardened samples were made by metallography and hardness traverse.
Rathod, M. J., Deore, H. A.
Vehicle Powertrain Test Bench Co-Simulation with a Moving Base Simulator Using a Pedal Robot2013-01-04104/8/2013
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
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
Snowmobile Brake Control SystemsJ1282_201204 (Historical)4/9/2012
This SAE Recommended Practice is intended to provide the minimum acceptable criteria for snowmobile hand brake control systems. This recommendation is not intended to cover competition vehicles nor is it intended to limit development of new and/or improved technology in controls. Although these recommendations are primarily addressed to hand control systems using an outer flexible conduit with a multiple strand inner cable or hydraulic type brake control system, the basic requirements of freedom of movement, strength, material, etc., will apply to any system.
Snowmobile Technical 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
Mechanical Systems Physics-of-Failure Analysis Experimental ValidationJ2869_201008 (Historical)8/30/2010
This report details continuing work examining the fatigue life durability of a US Army Trailer. This report describes, through example, a process to evaluate and reduce the experimental data needed for a Mechanical Systems Physics-of-Failure analysis. In addition the report describes the process used to validate the computer simulation models.
Ground Vehicle Reliability Committee
Development of a Self-Energizing Electro-Hydraulic Brake (SEHB)2007-01-423610/30/2007
A new hydraulic brake utilizing a self-energizing effect is developed at the Institute for Fluid Power Drives and Controls (IFAS). In addition to a conventional hydraulic braking actuator, it features a supporting cylinder conducting the braking forces into the vehicle undercarriage. The braking force pressurizes the fluid in the supporting cylinder and is the power source for pressure control of the actuator. The new brake needs no external hydraulic power supply. The only input is an electrical braking force reference signal from a superior control unit. One major advantage of the SEHB concept is the direct control of the actual braking torque despite friction coefficient changes. The prototype design, presented in this paper, is done in two phases. The first prototype is based on an automotive brake caliper. It is set up to gain practical experience about the hydraulic self-energisation and to prepare the laboratory automation environment. Active retraction is required for train brakes though, which cannot be done with automotive brakes. The second prototype therefore features a differential double acting braking cylinder with a pre-stressed spring for fail safe braking. A mechanical design systematics is presented which helps to map requirement specifications originating from a particular application to implementation in a structural design. The promising dynamic behavior of SEHB based on simulation results is presented.
Liermann, Matthias, Stammer, Christian, Murrenhoff, Hubertus
Application of Hydraulic Brake Hose to Motor Vehicles—Wheel End and AxleJ1406_200710 (Historical)10/4/2007
This SAE Recommended Practice covers the application of hydraulic brake hose (as defined by current issue of SAE J1401) as used to provide a flexible hydraulic connection between wheel end or axle brake system components on motor vehicles.
Automotive Brake and Steering Hose Standards Comm
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
Wheel and Brake Design and Test Requirements for Military AircraftARP1493A (Historical)7/9/2007
This document covers military aircraft wheel and brake equipment.
A-5A Wheels, Brakes and Skid Controls Committee
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
Snowmobile Brake Control SystemsJ1282_200302 (Historical)2/18/2003
This SAE Recommended Practice is intended to provide the minimum acceptable criteria for snowmobile hand brake control systems. This recommendation is not intended to cover competition vehicles nor is it intended to limit development of new and/or improved technology in controls. Although these recommendations are primarily addressed to hand control systems using an outer flexible conduit with a multiple strand inner cable or hydraulic type brake control system, the basic requirements of freedom of movement, strength, material, etc., will apply to any system.
Snowmobile Technical Committee
Automotive Hydraulic Brake System—Metric Tube ConnectionsJ1290_200210 (Historical)10/31/2002
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
Application of Hydraulic Brake Hose to Motor VehiclesJ1406_200204 (Historical)4/9/2002
This SAE Recommended Practice covers the application of hydraulic brake hose (as defined by current issue of SAE J1401) as used to provide a flexible hydraulic connection between brake system components on motor vehicles.
Automotive Brake and Steering Hose Standards Comm
Service Maintenance of SAE J1703 and J1704 Brake Fluids in Motor Vehicle Brake SystemsJ1707_200201 (Historical)1/16/2002
This SAE Recommended Practice provides basic recommendations for dispensing and handling of SAE J1703 and 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
From gullwing to vario-roofAUTOOCT01_0510/1/2001
The new Mercedes-Benz SL moves into the 21st century with an industry-first production electrohydraulic braking system and a next-generation folding hardtop. Technology is the design ethic that has produced the new-generation Mercedes-Benz SL, just as it was with the first direct-fuel-injection gullwing SL of the early 1950s. But the latest Mercedes-Benz, the fifth-generation SL, reaches far higher levels of sophistication, with the introduction of an electrohydraulic brake-by-wire system (claimed as a “first” for a road car), advanced folding hardtop, and a structure with high aluminum content. Engine developments slated for production are believed to include a bi-turbo V12, and Mercedes-AMG is already offering a 5.5-L supercharged V8 producing 350 kW (470 hp). It is half a century since Mercedes embarked on its SL (sports, light) program when, at a Daimler-Benz Board meeting in June 1951, the decision was made to re-enter motor racing at Formula 1 and sports racing levels. For its first post-war sports racing car, it took the standard 3.0-L engine from the stately 300 sedan, almost doubled its output, “and built a tubular frame and aluminum body” around it. The result-the 300 SL-evolved along aerospace-engineering lines, the fine steel tubes that formed its structure being welded together by hand. And to ensure rigidity, top-hinged, upward-opening doors that formed part of the roof-similar to a fighter aircraft's canopy-provided access to an interior that had the distinct ambience of an aircraft cockpit. It was those doors-dubbed gullwing-more than any other facet of this extraordinary car that were to guarantee the 300 SL a truly unique position in automotive history.
Birch, Stuart
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
Borate Ester Based Brake FluidsJ1704_200010 (Historical)10/1/2000
This SAE Recommended Practice was prepared to provide engineers, designers, and manufacturers of motor vehicles with a set of minimum performance standards which covers the next level of performance properties above those of the present SAE J1703 brake fluid standard. These fluids are not intended for use under arctic conditions or in braking systems requiring the use of mineral oil based hydraulic fluid. 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). These fluids are not designed to operate in a pumped or a clutch braking system, especially those hydraulic systems requiring a mineral oil based fluid.
Brake Fluids Standards Committee
Motor Vehicle Brake FluidJ1703_200010 (Historical)10/1/2000
This SAE Standard covers motor vehicle brake fluids of the nonpetroleum type for use in the braking system of any motor vehicle such as a passenger car, truck, bus, or trailer. These fluids are not intended for use under arctic conditions. 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).
Brake Fluids Standards Committee
Dynamometer Effectiveness Characterization Test for Passenger Car and Light Truck Brake Friction ProductsJ2430_199908 (Historical)8/30/1999
This SAE Recommended Practice establishes an inertia dynamometer test procedure, using exemplar caliper disc or drum brakes, to characterize the effectiveness of brake friction products for passenger cars and light trucks, up to and including 3500 kg GVW. SAE J2430 provides a method of characterizing friction material effectiveness, using vehicle specific brake hardware and test conditions that approximate those for U.S. mandated new vehicle brake tests.
Brake Dynamometer Standards Committee
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
RUBBER CUPS FOR HYDRAULIC ACTUATING CYLINDERSJ1601_199707 (Historical)7/1/1997
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
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