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2015-05-18 ...
  • May 18-20, 2015 (8:30 a.m. - 4:30 p.m.) - Troy, Michigan
Training / Education Classroom Seminars
Hydraulic brake systems, one of the most important safety features on many road vehicles today, must meet manufacturer and customer requirements in addition to Federal Motor Vehicle Safety Standards. This course will analyze automotive braking from a system's perspective, emphasizing legal requirements as well as performance expectations such as pedal feel, stopping distance, fade and thermal management. Calculations necessary to predict brake balance and key system sizing variables that contribute to performance will be discussed.
2015-05-10 ...
  • May 10, 2015 (1:30 p.m. - 5:30 p.m.) - Charleston, South Carolina
Training / Education Classroom Seminars
SAE International is pleased to offer this professional development seminar in conjunction with the SAE A-6 Aerospace Actuation, Control and Fluid Power Systems Committee meeting May 10 - 14, 2015 in Charleston, South Carolina. This four-hour short course provides an overview of hydraulic system design of recently developed business and commercial aircraft. Topics will include hydraulic principles, system architectures, power sources, and the main components and technologies of hydraulic systems including hydraulic power generation, filtration, fluid storage, distribution, sensing and control.
2015-04-14
Technical Paper
2015-01-1373
Yulong Lei, Hui Tang, Xingjun Hu, Ge Lin, Bin Song
With the continuous improvement of the road condition, commercial vehicles get to be faster and more overloaded than before, which puts higher pressure on the vehicle braking system. Conventional friction braking has been difficult to meet the needs of high-power commercial vehicle. The auxiliary brake equipment will become the future trend for commercial vehicle. Hydraulic retarder is superior secondary braking equipment. Previously hydraulic retarder research mainly focus on flow field analysis, the braking torque calculation, cascade system optimization and control methods for hydraulic retarder. The gas-liquid two-phase flow in working chamber is less researched. Based on this, this article discusses on the hydraulic retarder from two aspects, including CFD numerical modeling method, transient characteristics of oil-filling , which provides support for hydraulic retarder design and matching in the vehicle. The main contents and conclusions are as follows: 1.
2015-04-14
Technical Paper
2015-01-1300
Shuanlu Zhang, Changlu Zhao, ZhenFeng Zhao, Dong Yafei, Fukang Ma
The hydraulic free piston engine is a complex mechanical-electro-liquid system, in order to simplify the complex system of the single hydraulic free piston engine, a new method for the driving of hydraulic free piston engine is proposed. Hydraulic differential drive achieves the compression stroke automatically rather than special recovery system. The structure and principle of hydraulic differential drive free-piston engine is analyzed and the mathematical model is established based on the piston force analysis and the hydraulic system working principle. In addition, the control strategy of this novel hydraulic driving engine is also introduced. Finally, the transient results of dynamics are obtained through simulation. Then we make a compare with the hydraulic free piston engine from Innas Company. The results show that: 1) the simplified engine can achieve the similar performance of the Innas concept. 2) The maximum frequency or the maximum power of the engine is increased.
2015-04-14
Technical Paper
2015-01-1117
Yang Liu, Zechang Sun
Regenerative braking control for a four-wheel drive (4WD) electric vehicle equipped with a decoupled electro-hydraulic brake system was studied. The 4WD electric vehicle powertrain with four in-wheel motors was introduced, and the four motors could be controlled independently during the driving or braking operation modes, which have advantages on powertrain configurations and fuel economy improvement over the vehicles driven by a single motor. An electro-hydraulic brake system using a master cylinder integrated with brake pedal feel simulator, hydraulic brake booster and failure backup was adopted to guarantee the coordinate control between the regenerative force and the hydraulic force, whose brake pedal force and wheel cylinder pressure was decoupled. The energy flow of the 4WD electric vehicle was analyzed during braking, and the brake force distribution strategy between the front-rear axles, in-wheel motor regenerative braking and hydraulic braking was studied.
2015-04-14
Technical Paper
2015-01-1127
Wenbin Liu, Gangfeng Tan, Xiaoqing Tian, Zhiqiang Hu, Yuanqi Gao, Zhi Li, Junyi Yuan, Wei Liu
As a kind of an important auxiliary brake of heavy vehicle, hydraulic retarder has good performance for stability and braking sustainability. However, the hydraulic retarder is filled with air when the vehicle is traveling in non-braking state, and the Air-friction may reduce the vehicle transmission efficiency obviously.   The air density in retarder cavity can be decreased by pumping the gas, which can reduce the transmission power loss. The gas pumping in retarder cavity has an important influence on the retarder working stability. Firstly, the dynamic characteristics relationships between the vacuum degree and the change of flow resistance in retarder cavity are analyzed by the 3D fluid simulation in different driving conditions, and the stability boundary conditions of the Air-friction change is determined.
2015-04-14
Technical Paper
2015-01-1114
Can Wang, Bo Yang, Gangfeng Tan, YiRui Wang, Li Zhou
The tracked vehicle which is widely used in the large construction projects has excellent climbing and obstacle surmounting performance, and it also has good low-speed stability under extreme conditions. However, in this engineering environment of the complex terrain, because the vehicle’s motion states are complex and unpredictable, and the tracks are very easy to slip. At the same time, on consideration of the power match of the hydraulic driving system, the walking trajectory of this tracked vehicle is difficult to control. In order to improve the working stability of the vehicle hydraulic control system, on the basis of the vehicle dynamics model and hydraulic system model, the vehicle walking speed and trajectory control model are studied, and the closed loop control is set up. The result indicates that a good dynamic response and stability performance of the hydraulic driving system are verified.
2015-04-14
Technical Paper
2015-01-0159
Zhihui Tan, Zhenfu Chen, Xiaofei Pei, Jie Zhang, Xuexun Guo
Analogous to a vacuum boosted system, Electro-Hydraulic Braking System (EHB) supplies a braking force proportional to driver input, and is especially fit for electric vehicles (EV) and hybrid electric vehicles (HEV). As a key component of EHB, this paper introduces a new integrated master cylinder which is developed from the traditional one. However, the master cylinder is driven by the pump rather than the vacuum booster. Even if the pump fails, the cylinder can also build proper pressure. Meanwhile, in the EHB system, the connection between master cylinder and pedal is structurally decoupled. So the cylinder and pedal can be independently designed and controlled. Furthermore, the pressure surge in the master cylinder will not affect pedal feeling. In this paper, the EHB system is designed including two parts: master cylinder and pedal stroke simulator.
2015-04-14
Technical Paper
2015-01-0654
Bing Zhu, Jiapeng Gong, Jian Zhao, Jian Wu, Weiwen Deng
The permanent-magnet DC motor, which directly connected to the hydraulic pump, is a significant component of hydraulic control unit (HCU) in an anti-lock braking system (ABS). It drives the pump to dump the brake fluid from the low-pressure accumulator back to master cylinder and make sure the pressure decrease of wheel cylinder in ABS control. Obviously, the motor should run fast enough to provide sufficient power and prevent the low-pressure accumulator from fully charging. However, the pump don’t need always run at full speed for the consideration of energy conservation and noise reduction. Therefore, it is necessary to accurately regulate the speed of the DC motor in order to improve quality of ABS control. In this paper, a DC motor model was established using Matlab/Simulink software at first. Then the ABS hydraulic brake system model was present in AMESim.
2015-04-14
Technical Paper
2015-01-0658
Min Zhou, Lifu Wang, Jie Zhang, Nong Zhang
Hydraulic suspensions with different interconnecting configurations can decouple suspension mode and improve performance of a particular mode. In this paper, two types of interconnected suspensions are compared for off-road vehicle trafficability. Traditionally, anti-roll bar, a mechanically interconnected suspension system, connecting left and right suspension, decouples roll mode from the bounce mode and results in a stiff roll mode and a soft bounce mode, which is desired. However, anti-roll bars fail to connect the front wheel motions with the rear’s, thus the wheels’ motions in the warp mode are affected by anti-roll bars and it results an undesired stiffened warp mode. A stiffened warp mode limits the wheel-ground contact and may cause one wheel lift up especially during off-road drive. In contrast to anti-roll bars, two types of hydraulic suspensions which interconnect four wheels (for two-axis vehicles) can further decouple warp mode from other modes.
2015-04-14
Technical Paper
2015-01-1211
Zhuoping Yu, Caitao Jian, Songyun Xu, Lu Xiong
This paper is to research the dynamic response of active power source (APS) of electro hydraulic brake (EHB) system, which is a new design system. The dynamic response of APS could impact the effectiveness of brake system, the reason is that the slow-response of APS will cause the slow speed of building pressure and increasing the braking distance. So researching the dynamic response of active power source is very important for brake system. First of all, the part is about the components and working principle of EHB system and some parameters of active power source. EHB systemconsists of active power source (APS), pedal feel emulator (PFE), electro control unit (ECU) and hydraulic control unit (HCU). APS includes motor, master cylinder and retarding mechanism consisting of warm, gear and gear rack. Secondly, this paper proposes a restricted distribution control strategy——the control strategy of restricted distribution (CSRD).
2015-04-14
Technical Paper
2015-01-0617
Jie Zhang, Xiao Chen, Bangji Zhang, Lifu Wang, Shengzhao Chen, Nong Zhang
Well-deigned suspension system plays an important role in improving ride comfort. Underground mining vehicles which work in harsh conditions commonly employ leaf spring suspension to provide large stiffness and damping while be compact in size. Another characteristic of the mining vehicle is that its sprung mass varies significantly when loaded/unloaded. The leaf spring suspension has to be designed very stiff to meet the full-loaded requirement, therefore when the vehicle is unloaded, the stiff leaf spring damage the ride quality and expose the passengers to noise, vibration and harshness. Since the hydraulic suspension systems can provide better ride comfort, the paper proposes a design of adding an interconnected hydraulic system to resist bounce motions to share the vertical load with the leaf spring, which therefore can be designed softer. Furthermore, The hydraulic system also increases the suspension stiffness in the pitch mode to prevent vehicle from large pitch motions.
2015-04-14
Technical Paper
2015-01-1612
Wei Liu, Gangfeng Tan, Jiafan Li, Xin Li, Fuzhao Mou, Yongqiang Ge
The hydraulic retarder is a significant auxiliary braking device for the heavy duty vehicle. Traditionally, cooling circulation of the hydraulic retarder was coupled with the engine cooling system, and the thermal energy of the transmission oil would be cooled by the engine radiator ultimately. For this scheme, radiator’s spare heat removal capacity could be fully utilized whereas the cooling system is very complicated and is hard to maintain. Furthermore, the corresponding of thermal management system lags behind the power change of the retarder. In this research, integrated cooling evaporation system is developed for the hydraulic retarder, which makes the cooling water contact with the transmission oil through the wall of the fixed wheel so that it can rapidly response to the thermal variation of the retarder, keep the stability of the oil temperature and meanwhile reduce the risk of cooling medium leakage.
2015-04-14
Journal Article
2015-01-0656
Amir Soltani, Francis Assadian
A new control strategy for wheel slip control, considering the complete dynamics of the electro-hydraulic brake (EHB) system, is developed and experimentally validated in Cranfield University’s HiL system. The control system is based on closed loop shaping Youla-parameterisation method. The plant model is linearized about the nominal operating point, a Youla parameter is defined for all stabilizing feedback controller and control performance is achieved by employing closed loop shaping technique. The stability and performance of the controller are investigated in frequency and time domain, and verified by experiments using real EHB smart actuator fitted into the HiL system with driver in the loop.
2015-04-14
Technical Paper
2015-01-0230
Shuhan Tang, Yanfang Liu, Xiao Han
Abstract As a significant control component of vehicles, automatic transmissions should have failure protection function. The failure protection function partly is determined by the hydraulic control system. However traditional design could not cover all of failures, and there is no general design method. A design method is proposed for designing the shift control oil circuit of the hydraulic control system with the failure protection function. The design method is applied to optimize the hydraulic control system of a six-speed automatic transmission. The function of the optimized hydraulic control system is confirmed by the dynamic simulation. The results show that the design method can simplify the hydraulic control system without losing any original functions. The proposed design method is proved to be suitable for all kinds of hydraulic control systems of automatic transmissions.
2015-04-14
Journal Article
2015-01-1611
Wei Liu, Gangfeng Tan, Xuexun Guo, Jiafan Li, Yuanqi Gao, Wei Li
When the hydraulic retarder is working in the heavy-duty vehicle, almost all the braking power is transformed into the thermal energy of the transmission oil. The spare heat removal capacity of engine’s cooling system could be taken full advantage for cooling the retarder. However, the relative long distance of the engine and the retarder increases the risky leakage of the cooling circuit. Furthermore, the development trend of heavy load and high speed vehicle directs the significant increase in the thermal load of the hydraulic retarder, which even higher than the engine power. Conventional engine cooling system could not meet the demand of the hydraulic retarder heat rejection within the same installation space. In this research, independent two-phase evaporator was adopted to strengthen the coolant heat absorption capacity from the transmission fluid at the oil outlet of the retarder by means of the vacuum flow boiling heat transfer.
2015-04-14
Technical Paper
2015-01-0323
Jörn Getzlaff, Tobias Dost, Thomas Lambert, Erik Lenk
Abstract The global development of oil prices and ongoing discussions with regard to meet future CO2-emission commitments necessitate new technologies and concepts in individual motor car traffic. While hybridization and electrification become more and more important on a small scale, the improvement in efficiency of conventional drive, especially in respect of SI engines, currently offers the highest potential in reducing fuel consumption and exhaust emissions. Thereby valve trains play a key role in the optimization of SI engines e. g. in connection with technologies and processes such as carburation, combustion, HCCI, gas exchange, lean operation etc. Modern valve train systems entering mass production are despite of the fact of being called fully variable, yet cam-actuated systems. Thus variability and application are limited compared to direct (non-cam-actuated) engine control systems.
2015-04-14
Technical Paper
2015-01-0231
Qingkai Wei, Yulong Lei, Xingzhong Li, Boqin Hu, Zhengwei Liu, Bin Song
Abstract Gear-shift process of automatic transmission (AT) can be achieved with hydraulic control system which operates clutches or brakes' engagement or disengagement. According to the state of engagement elements, gear-shift process can be divided into torque phase and inertia phase. This article analyses gear-shift process of automatic transmission with the lever analogy and got the variation of the transmission's output torque. Then, the control principle of clutch to clutch shift is studied. This article takes power on up shift as study example and minimum of transmission output torque fluctuations during shifting as control target. Then this article analysis two control principles including inertia phase engine & transmission integrated control principle and entire shift process engine & transmission integrated control principle.
2015-03-10
Technical Paper
2015-01-0017
Yufeng Wang, Zhizhong Wang, Liangyao Yu, Jian Song
Abstract Many types of brake by wire systems have been developed in past years, such as EMB (Electro-mechanical Brake) [1, 2], DEHB (Distributed Electro-hydraulic Braking System) [3] and EWB (Electric Wedge Brake) [4]. When the vehicle need braking in long period such as waiting for traffic light or downhill braking in those brake systems, the current will sustain very long time with very high level. This current will result in high temperature in motor, and will damage the power supplier. When a new DEHB is developing, a holding function is added in this DEHB. The holding function is self-energized when holding the brake, and automatic released after the brake. Advantageously, after activation of the holding function, the current delivered to the motor for braking is substantially decreased, especially, will be zero when the brake torque is not need to adjust.
2015-02-27
WIP Standard
AS6116A
This SAE Aerospace Standard (AS) establishes the requirements for externally swaged aluminum tube fittings on aluminum tubing with flareless separable fitting ends for use in hydraulic supply and return aerospace fluid systems including pneumatic, coolants, and fire extinguishers up to a maximum operating pressure of 1500 psig (10 340 kPa) and a maximum operating temperature range of -65 to +225 °F (-54 to +107 °C).

This specification covers a common aluminum fitting that may be used for a range of operating pressures up to 1500 psi with different tubing materials and tubing wall thicknesses, and is assembled with the same tooling in accordance with AS6124. Table 12 shows applicable aerospace fitting part number standard and tubing materials and operating pressures.

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