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Training / Education
2014-08-18
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. Major components of a brake system, including calipers, boosters, master cylinders, drum brakes, and park brakes will be presented in detail highlighting the many design variations. An overview of the chassis control components and operating principles will be presented with an emphasis on ABS, traction control and stability control. This course has been approved by the Accreditation Commission for Traffic Accident Reconstruction (ACTAR) for 18 Continuing Education Units (CEUs).
WIP Standard
2014-04-04
This SAE Aerospace Standard (AS) defines the requirements for polytetrafluoroethylene (PTFE) line, metallic reinforced, hose assemblies suitable for use in aerospace hydraulic, fuel and lubricating oil systems at temperatures between -67 °F and 450 °F for Class I assemblies, -67 °F and 275°F for Class II assemblies, and at nominal pressures up to 1500 psi. The hose assemblies are also suitable for use within the same temperature and pressure limitations in aerospace pneumatic systems where some gaseous diffusion through the wall of the PTFE liner can be tolerated.

The use of these hose assemblies in pneumatic storage systems is not recommended. In addition, installations in which the limits specified herein are exceeded, or in which the application is not covered specifically by this standard, for example oxygen, shall be subject to the approval of the procuring activity.

Technical Paper
2014-04-01
Wei Yang, Wenku Shi, Chunxue Chen
Aiming at the abnormal vibration of driver seat of a passenger car in idle condition, vibration acceleration of engine, frame and seat rail was tested to identify vibration sources. Order tracking and spectrogram analysis indicated that the second order self-excitation of engine was the main cause. To solve the problem, semi-active controlled hydraulic engine mount with air spring of which characteristics could shift between a high dynamic stiffness and a low one was applied. Then the structure and principle of the mount with variable characteristics was introduced and control mode was analyzed. Dynamic characteristics were obtained by bench test. With sample mount applied, vibration of seat rail was tested again in multiple vehicle and engine working conditions. Dates showed that abnormal vibration in idle condition was extremely reduced and the mount could also meet the requirement of engine to dynamic stiffness in driving conditions.
Technical Paper
2014-04-01
Yang Liu, Zechang Sun, Wenbin JI
Abstract 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.
Technical Paper
2014-04-01
Ryan M. Ashby, JongYun Jeong, Shreesha Y. Rao, Gary J. Heydinger, Dennis A. Guenther
This research was to model a 6×4 tractor-trailer rig using TruckSim and simulate severe braking maneuvers with hardware in the loop and software in the loop simulations. For the hardware in the loop simulation (HIL), the tractor model was integrated with a 4s4m anti-lock braking system (ABS) and straight line braking tests were conducted. In developing the model, over 100 vehicle parameters were acquired from a real production tractor and entered into TruckSim. For the HIL simulation, the hardware consisted of a 4s4m ABS braking system with six brake chambers, four modulators, a treadle and an electronic control unit (ECU). A dSPACE simulator was used as the “interface” between the TruckSim computer model and the hardware.
Technical Paper
2014-04-01
Jie Ni, Lifu Wang
Abstract In this paper, a torsion-eliminating Hydraulically Interconnected Suspension (THIS) is proposed for the first time to reduce the undesired articulation (warp) stiffness of a two-axis vehicle. The dynamic characteristics of a typical sport utility vehicle (SUV) fitted with the THIS is investigated in the frequency domain. The equations of motion of the coupled mechanical and hydraulic sub-systems are presented. The vehicle basic mechanical sub-system is modeled as a 7 degrees of freedom (DOF) mass-spring-damper system. The hydraulic impedance method is employed to model the fluid sub-system. The relationships between the dynamic fluid states, i.e. pressures and flows, are determined by transfer matrices. Then the mechanical and hydraulic sub-systems are coupled through the mechanical-fluid boundary conditions. Based on fluid hydraulic impedance method, the characteristic equations of this mechanically and hydraulically coupled system are derived with a state vector including the displacements and velocities of mechanical system and the pressure at the mechanical-hydraulic boundary section.
Technical Paper
2014-04-01
Haohua Hong, Lifu Wang, Minyi Zheng, Nong Zhang
This paper employs the motion-mode energy method (MEM) to investigate the effects of a roll-plane hydraulically interconnected suspension (HIS) system on vehicle body-wheel motion-mode energy distribution. A roll-plane HIS system can directly provide stiffness and damping to vehicle roll motion-mode, in addition to spring and shock absorbers in each wheel station. A four degree-of-freedom (DOF) roll-plane half-car model is employed for this study, which contains four body-wheel motion-modes, including body bounce mode, body roll mode, wheel bounce mode and wheel roll mode. For a half-car model, its dynamic energy contained in the relative motions between its body and wheels is a sum of the energy of these four motion-modes. Numerical examples and full-car experiments are used to illustrate the concept of the effects of HIS on motion-mode energy distribution. The obtained simulation results show that the installed HIS system is able to reduce the energy level in the body-dominated roll motion-mode, and it has negligible effect in the bounce mode.
Technical Paper
2014-04-01
Tae-Sang Park, Sungho Jin, Jeon IL Moon, Seung-Han Yang
Abstract As is well known, the brake systems of vehicles are used in order to decelerate or stop the vehicle while the driving. The operational principle of the brake is the conversion of kinetic energy into thermal energy. In this case, the thermal energy is released to the atmosphere. Recently, electromechanical brakes (EMB) were developed in order to replace hydraulic brake calipers. Such brake-by- wire systems are composed of an electronic pedal, electronic control unit (ECU), wire, and an electromechanical caliper. A typical electromechanical brake is similar to existing floating brakes. In other words, an inner pad pushes out one side of a disc driven by the energy of a motor; by means of a screw-thread gear. Then, the caliper slides in the opposite direction by reaction force and moves the outer pad toward the other side of the disc. Then pads clamp both sides of the rotating disc and stop the wheel. While effective, this design has the problem that there is a difference in the wear of the inner and outer pads.
Technical Paper
2014-04-01
Justin T. Wagner, Thomas Bradley
Abstract With the recent adoption of fuel economy and emissions regulations for medium and heavy duty vehicles by the Environmental Protection Agency and the National Highway Traffic Safety Agency, new technologies to meet these targets are being developed. One such vehicle architecture that could meetthese regulations is hydraulic hybridization. Medium- and heavy-duty vehicles which operate on high intensity drive cycles (city buses, delivery vehicles, refuse vehicles, etc.) are good candidates for hydraulic hybridization due to the drive cycle intensity and the speeds at which they operate. This paper, through MATLAB/Simulink modeling, investigates the overall effectiveness of hydraulic hybridization through the selection of individual hydraulic parameters. With the effect of each hydraulic parameter determined, this paper defines a design of experiments to optimize the parameters for specific drive cycles to help determine the feasibility of the hydraulic technology for these classes of vehicles.
WIP Standard
2014-03-31
This SAE Aerospace Recommended Practice (ARP) establishes a method for evaluating the particulate matter extracted from theh working fluid of a hydraulic system or component using a membrane. The amount of particulate matter deposited on the membrane due to filtering a given quantity of fluid is visually compared against a standard membrane in order to provide an indication of the cleanliness level of the fluid. A particular feature of this method is the membrane preparation to achieve an even particulate distribution on the membrane suitable for other applications. Membrane evaluation using standard membranes, described in this document, is an alternative technique to counting with either an optical microscope (ARP598) or an automatic particle counter (ISO 11500). The latter particle counting procedures are considered more rpecise. This procedure shall not be used as an alternative to particle counting unless agreed to by the customer since the results by this procedure may differ from those by particle counting, even though the standard membrane correlates to a specific particle count.
WIP Standard
2014-03-28
This information report is intended to provide reference material for the selection and use of fire-resistant fluids in the hydraulic systems of off-road work machinery with separate hydraulic oil sump.
WIP Standard
2014-03-25
This SAE Aerospace Recommended Practice (ARP) is intended as a guide in defining the requirements for aerospace piston separated hydraulic accumulators, including details pertinent to the design, fabrication, and performance of the accumulator. This type of accumulator has a piston separator and contains both high-pressure gas and fluid. The accumulator is used in aerospace hydraulic systems of the following types as defined in SAE AS 5440 with design operating pressures of up to 8000 psi (55,160 kPa). Type I: -65 to +160 °F (-54 to +71 °C) fluid temperature Type II: -65 to +275 °F (-54 to +135 °C) fluid temperature For commercial aerospace or helicopter applications, the information and guidelines of SAE ARP 4752 or SAE ARP 4925 respectively, are considered.
WIP Standard
2014-03-18
This SAE Standard provides general, dimensional and performance specifications for the most common hoses used in hydraulic systems on mobile and stationary equipment. The general specifications contained in Sections 1 through 12 are applicable to all hydraulic hoses and supplement the detailed specifications for the 100R-series hoses contained in the later sections of this document. (See Tables 1A and 1B). This document shall be utilized as a procurement document only to the extent as agreed upon by the manufacturer and user. The maximum working pressure of a hose assembly comprising SAE J517 hose and hose connectors per SAE J516, SAE J518, SAE J1453, etc., shall not exceed the lower of the respective SAE maximum working pressure values. When using SAE J517 hose for marine applications, see SAE J1475, SAE J1942 and SAE J1942-1. The SAE J517 100R9, 100R10 and 100R11 hoses are discontinued due to lack of demand. For DOD orders see Appendix C. The SAE J517 100R1A, 100R2A, 100R2B and 100R 2BT are discontinued due to lack of demand.
WIP Standard
2014-03-17
This specification covers the general requirements for aircraft tank mounted, centrifugal type, fuel booster pumps, used for engine fuel feed and / or fuel transfer.
Standard
2014-03-17
Scope is unavailable.
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