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Viewing 241 to 270 of 10028
2014-04-01
Technical Paper
2014-01-0928
Daryl R. Poirier, Ravindra Patil, Robert Geisler, Joseph Schudt
Abstract The automotive industry is under great pressure to reduce vehicle mass for both cost and fuel economy gains. A significant contributor to body and suspension structure mass is peak vertical loads, primarily entering the body structure through the jounce bumper to body interface. This paper focuses on the successful development of “Loads Management Striker Caps” for the 2013 Cadillac ATS front and rear suspension. Component design and development of the striker caps was executed using explicit finite element analysis tools. Multi-body dynamics vehicle models were used to set component requirements and confirm striker cap performance for the vehicle during peak vertical events. The “Loads Management Striker Caps” ultimately reduced peak strut/shock tower loads by 40% in the front suspension and 25% in the rear suspension. This resulted in significant body and chassis mass savings, contributing to the Cadillac ATS's class leading curb weight.
2014-04-01
Technical Paper
2014-01-0929
Changxin Wang, Wenku Shi, Qinghua Zu
Abstract Aiming at the difficulty of sovling the stiffness calculation of taper-leaf spring with variable stiffness, a combined method was proposed, which combine superposition method and finite difference method. Then the calculation results of different differential segments were compared with experimental results. The compared results show that the proposed method is effective and simple. So it has some practical significance in designing the taper-leaf spring. In addition, based on the stiffness test of the taper-leaf spring, the proper adjustments to the correction factor of the single parabolic leaf spring stiffness formula was recommended(ξ =0.92-0.96).
2014-04-01
Technical Paper
2014-01-0714
Sanghun Cho, Taewan Gu, Eunyoung Yoo, Youngkyu Jeong, Baegsu Joo
Abstract In automotive software developments, since the types of software functionalities are depending on automotive engineering domains such as powertrain, body, and chassis, software logic and data processing, code complexity, and its reliability are also depending on them. Therefore, it has some challenges that monolithic code quality measures are applied to software code for all domains. In addition, imprecise criteria for the measures also can make software developers and testers confused whether their code verifications are enough or not. This paper proposes domain-specific code quality measures and precise criteria by combining a new functionality model, named Abstract Function Model (AFM), and shows results of automotive software functionality analysis using the model. Using 8 real automotive software projects, we derived statistics of software code on specific automotive engineering domain and identified code quality measures from the statistics.
2014-04-01
Technical Paper
2014-01-0331
Masayuki Naito, Yasuhiro Koike, Shintaro Osaki, Shinichiro Morishita, Nanhao Quan
Abstract HEV and EV markets are in a rapid expansion tendency. Development of low-cost regenerative cooperation brake system is needed in order to respond to the consumers needs for HEV and EV. Regenerative cooperation brake system which HEV and EV are generally equipped with has stroke simulator. We developed simple composition brake system based on the conventional ESC unit without the stroke simulator, and our system realized a low-cost regenerative cooperation brake. The key technologies are the quiet pressurization control which can be used in the service application, which is to make brake force depending on brake travel, by gear pump and the master cylinder with idle stroke to realize regenerative cooperation brake. Thanks to the key technologies, both the high regenerative efficiency and the good service brake feeling were achieved.
2014-04-01
Technical Paper
2014-01-1717
Robert Lloyd
Abstract A hydro-mechanical transmission is described that approximates the “gearing” performance of a continuously variable transmission and incorporates all functions required for hydraulic regenerative braking. Other characteristics such as efficiency, noise, and responsiveness, match or exceed that of present day conventional automatic transmissions. Performance and physical sizing are shown for passenger vehicle, bus and truck transmissions.
2014-04-01
Technical Paper
2014-01-1740
Jiageng Ruan, Paul Walker
Abstract Regenerative braking energy recovery bears significance in extending the driving mileage of electric vehicles (EVs) while fulfilling real-time braking demands. Braking energy strategy plays a significant role in improving the regenerative braking performance and ensuring braking safety. This paper presents a regenerative braking energy recovery strategy for an example EV with a two-speed Dual Clutch Transmission (DCT). The two-speed DCT, with simple structure, can effectively extend the active vehicle speed-range for regenerative braking. Meanwhile, a shifting strategy is proposed for the DCT, working with the presented braking energy recovery strategy, to optimize the brake force distribution between front and rear wheels, motor and friction brake force. The EVs' model with the proposed regenerative braking strategy and the optimal shifting schedule was established and implemented in Matlab/Simulink.
2014-04-01
Technical Paper
2014-01-1742
Yao Fu, Yulong Lei, Ke Liu, Yuanxia Zhang, Huabing Zeng
Abstract In a traditional shift control strategy, the gear range is selected based on the throttle opening and the vehicle speed. The disadvantage of two-parameter based system is that the shift map is lack of adaptability in certain special conditions. The driving environment and the true intentions of the drivers are not fully taken into account by the shift control system. Therefore, improving the feasibility of the shift control strategy for the true intentions of the driver and driving environment is of great significance. Under braking conditions, Automatic transmission shift map with two parameters is unable to use engine braking effectively, which affects the drivability and safety of vehicles greatly. This paper presents a newly developed shift control strategy under braking conditions. First of all, the necessity of engine braking was analyzed.
2014-04-01
WIP Standard
J2204
This SAE Standard applies to the usage of tires of the same nominal size and tread type, but with different outside diameter for articulated front-end loaders. Articulated four-wheel-drive front-end loader performance and component life can be affected by excessive differences in the tire outside circumference and/or diameter. The purpose is to provide specific guidelines for the usage of tires with different outside circumference and/or diameter on articulated front-end loaders.
2014-04-01
Collection
This technical paper collection is focused on vehicle dynamics and controls using modeling and simulation, and experimental analysis of passenger cars, heavy trucks, and wheeled military vehicles. The papers address active and passive safety systems to mitigate rollover, yaw instability and braking issues; driving simulators and hardware-in-the-loop systems; suspension kinematics and compliance, steering dynamics, advanced active suspension technologies; and tire force and moment mechanics.
2014-04-01
Collection
This technical paper collection focuses on new theory, formulation and modeling of amplitude-, frequency- and temperature-dependent nonlinear components/systems such as rubber and hydraulic mounts or bushings, shock absorbers, and any joint friction/damping; dynamic characterization through lab and field testing; Linearization methodology; Model validation, application, and sensitivity analysis in vehicle system/subsystem simulations; Nonlinear system identification, modeling, and application in testing accuracy improvement, etc.
2014-04-01
Collection
This technical paper collection presents papers on steering and suspension related topics as it applies to ground vehicles. Papers for this session address new approaches as well as advances in application of steering, suspension related technologies.
2014-04-01
Journal Article
2014-01-0325
Michael Flad, Simon Rothfuss, Gunter Diehm, Sören Hohmann
Brake pedal feedback is important for driver's perception during the driving task as well as the pedal feel is an important factor in customer satisfaction. Therefore, a force emulation device is beneficial during the design phase to evaluate the pedal characteristic. Such a system is also needed for driving simulators. Usually, brake feedback systems in simulators rely on passive elements like springs and dampers to emulate the force. This does not allow the implementation of an arbitrary nonlinear pedal force characteristic. In this paper we propose an active pedal feedback simulator which can emulate an arbitrarily customizable and online adjustable brake pedal characteristic. The particular advantage of our pedal simulator is that the system can also emulate the exact pedal dynamics. This is advantageous compared to other active brake feedback simulators which rely on hydraulic actors.
2014-04-01
Journal Article
2014-01-0245
Philip Axer, Daniel Thiele, Rolf Ernst, Jonas Diemer, Simon Schliecker, Kai R. Richter
Ethernet is the hottest candidate for future in-car communication architecture, promising much higher bandwidth, flexibility and reduced costs. In the coming years, Ethernet will likely evolve from a separate communication medium for special applications like surround-view cameras and infotainment to a central communication infrastructure as a backbone technology. To make this transition, many difficult design decisions have to be made in order to make the technology suitable for the stricter time and safety requirements of todays and future cars. There are a lot of potential real-time effects that must be taken into account. To guide these design decisions, it is necessary to analyze the various architecture concepts with respect to load, performance and real-time capabilities. In this paper, we present different design space axes of Ethernet and propose a methodology of assessing and comparing them.
2014-04-01
Technical Paper
2014-01-0999
Klaus Greven, Manikandan Loganathan
Abstract The Counter Pressure Casting (CPC) process is particularly suited for the production of aluminum suspension components like wheel carriers or steering knuckles. Using a typical AlSi7Mg alloy such as A356 or EN AC-42100, yield strength above 260 MPa and elongation rates above 8% are possible in a high volume production. Although these are very good values for aluminum castings, the yield strength has to be improved to increase the light weight potential of such components. The present work shows how this goal can be achieved by the development of a new aluminum casting alloy. Besides the modification of Si and Mg content, the addition of Cr leads to an additional dispersion hardening effect. In this way, yield strength above 310 MPa combined with an elongation of 7% can be assured in the CPC process after a T6 heat treatment.
2014-04-01
Technical Paper
2014-01-0123
Mingyuan Bian, Long Chen, Yugong Luo, Keqiang Li
Abstract A new dynamic tire model for estimating the longitudinal/lateral road-tire friction force was derived in this paper. The model was based on the previous Dugoff tire model, in consideration of its drawback that it does not reflect the actual change trend that the tire friction force decreases with the increment of wheel slip ratio when it enters into the nonlinear region. The Dugoff model was modified by fitting a series of tire force data and compared with the commonly used Magic Formula model. This new dynamic friction model is able to capture accurately the transient behavior of the friction force observed during pure longitudinal wheel slip, lateral sideslip and combined slip situation. Simulation has been done under different situations, while the results validate the accuracy of the new tire friction model in predicting tire/road friction force during transient vehicle motion.
2014-04-01
Technical Paper
2014-01-0115
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.
2014-04-01
Technical Paper
2014-01-0117
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.
2014-04-01
Technical Paper
2014-01-0156
Austin Gurley
Abstract Selection of springs and dampers is one of the most important considerations when finalizing a race car suspension design. It is also one of most complex due to the dynamic interaction of the vehicle with the ground. Current tuning methods for spring and dampers' effect on vehicle ride can be based on simplified dynamic models of the vehicle, such as the quarter-car model. While efficient computationally, the traditional quarter-car model does not account for the non-linear variation in grip seen by a fluctuating contact-patch. Both amplitude and frequency of suspension oscillation contribute to loss of tire grip. The method can be improved by incorporation of a dynamic tire model, though resulting in non-linear effects. An improved ‘rolling quarter-car’ model is created, which includes the effect of dynamic tire forces in the analysis of improved grip. Using typical Formula SAE race car, characteristics as a test case, a linearized dynamic model is made.
2014-04-01
Technical Paper
2014-01-0146
Lee Carr, Dan Barnes, Jennifer Crimeni
Abstract Prior to the widespread implementation of ABS brake technology in light vehicles, driver training often included instruction to “pump the brakes” to avoid locking the wheels. Many driver education programs now recommend maintaining high brake pedal force and relying on ABS. It is sometimes asserted that drivers desiring to stop a vehicle quickly still “pump the brakes”. Investigators sought to understand whether drivers desiring to decelerate quickly pump the brakes, especially in a way that may deplete the vacuum stored in a vehicle's brake booster if so equipped, or whether they apply the brakes in a manner corresponding to their desired deceleration. The National Highway Traffic Safety Administration (NHTSA) conducted a testing program to examine driver braking behavior in crash avoidance maneuvers.
2014-04-01
Technical Paper
2014-01-0087
Shinhoon Kim, John McPhee, Nasser Lashgarian Azad
Abstract A compact sized vehicle that has a narrow track could solve problems caused by vehicle congestion and limited parking spaces in a mega city. Having a smaller footprint reduces the vehicle's total weight which would decrease overall vehicle power consumption. Also a smaller and narrower vehicle could travel easily through tight and congested roads that would speed up the traffic flow and hence decrease the overall traffic volume in urban areas. As an additional benefit of having a narrow track length, a driver can experience similar motorcycle riding experience without worrying about bad weather conditions since a driver sits in a weather protected cabin. However, reducing the vehicle's track causes instability in vehicle dynamics, which leads to higher possibility of rollovers if the vehicle is not controlled properly. A three wheel personal vehicle with an active tilting system is designed in MapleSim.
2014-04-01
Technical Paper
2014-01-0878
Adam C. Reid, David Philipps, Fredrik Oijer, Inge Johansson, Moustafa EL-Gindy
Abstract The rigid-ring tire model is a simplified tire model that describes a tire's behaviour under known conditions through various in-plane and out-of-plane parameters. The complex structure of the tire model is simplified into a spring-mass-damper system and can have its behaviour parameterized using principles of mechanical vibrations. By designing non-linear simulations of the tire model in specific situations, these parameters can be determined. They include, but are not limited to, the cornering stiffness, vertical damping constants, self-aligning torque stiffness and relaxation length. In addition, off-road parameters can be determined using similar methods to parameterize the tire model's behaviour in soft soils. By using Finite Element Analysis (FEA) modeling methods, validated soil models are introduced to the simulations to find additional soft soil parameters.
2014-04-01
Technical Paper
2014-01-0859
Haizhen Liu, Weiwen Deng, Changfu Zong, Jian Wu
Abstract 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.
2014-04-01
Technical Paper
2014-01-0849
Xinxin Shao
Abstract In this paper, a passive anti-pitch anti-roll hydraulically interconnected suspension is proposed for compromising the control between the pitch and roll mode of the sprung mass. It has the advantage in improving the directional stability and handling quality of vehicles during steering and braking manoeuvres. Frequency domain analysis of a 7-DOF full-car model with the proposed system is presented. The modeling of mechanical subsystem is established based on the Newton's second law. Then the mechanical-hydraulic system boundary conditions are developed by incorporating the hydraulic strut forces into the mechanical subsystem as externally applied forces. The hydraulic subsystem is modelled by using the impedance method, and each circuit are determined by the transfer matrix method. And then the modal analysis method is employed to perform the vibration analysis between the vehicle with the conventional suspension and the proposed HIS.
2014-04-01
Technical Paper
2014-01-0847
Andrew Hall, John McPhee
Abstract Physical rig testing of a vehicle is often undertaken to obtain experimental data that can be used to ensure a mathematical model is an accurate representation of the vehicle under study. Kinematics and Compliance (K&C) testing is often used for this purpose. The relationship between the hard point locations and compliance parameters, and K&C characteristics of a suspension system is complex, and so automating the process to correlate the model to the test data can make the exercise easier, faster and more accurate than hand tuning the model. In this work, such a process is developed. First, the model parameters are adjusted, next a simulation is run, before the results are read and post processed. This automation processed is used in conjunction with an optimization procedure to carry out the K&C correlation.
2014-04-01
Technical Paper
2014-01-0445
Flaura Winston, Catherine McDonald, Venk Kandadai, Zachary Winston, Thomas Seacrist
Abstract Driving simulators offer a safe alternative to on-road driving for the evaluation of performance. In addition, simulated drives allow for controlled manipulations of traffic situations producing a more consistent and objective assessment experience and outcome measure of crash risk. Yet, few simulator protocols have been validated for their ability to assess driving performance under conditions that result in actual collisions. This paper presents results from a new Simulated Driving Assessment (SDA), a 35- to-40-minute simulated assessment delivered on a Real-Time® simulator. The SDA was developed to represent typical scenarios in which teens crash, based on analyses from the National Motor Vehicle Crash Causation Survey (NMVCCS). A new metric, failure to brake, was calculated for the 7 potential rear-end scenarios included in the SDA and examined according two constructs: experience and skill.
2014-04-01
Technical Paper
2014-01-0874
Edoardo Sabbioni, Federico Cheli, Matteo Riva, Andrea Zorzutti
Abstract For passenger cars, individual tyre model parameters, used in vehicle models able to simulate vehicle handling behavior, are traditionally derived from expensive component indoor laboratory tests as a result of an identification procedure minimizing the error with respect to force and slip measurements. Indoor experiments on agricultural tyres are instead more challenging and thus generally not performed due to tyre size and applied forces. However, the knowledge of their handling characteristics is becoming more and more important since in the next few years, all agricultural vehicles are expected to run on ordinary asphalt roads at a speed of 80km/h.
2014-04-01
Technical Paper
2014-01-0876
Barys Shyrokau, Dzmitry Savitski, Danwei Wang
Abstract Nowadays there is a tendency to implement various active vehicle subsystems in a modern vehicle to improve its stability of motion, handling, comfort and other operation characteristics. Since each vehicle subsystem has own limits to generate supporting demand, their potential impact on vehicle dynamics should be analyzed for steady-state and transient vehicle behavior. Moreover, the additional research issue is the assessment of total energy consumption and energy losses, because a stand-alone operation of each vehicle subsystem will provide different impact on vehicle dynamics and they have own energy demands. The vehicle configuration includes (i) friction brake system, (ii) individual-wheel drive electric motors, (iii) wheel steer actuators, (iv) camber angle actuators, (v) dynamic tire pressure system and (vi) actuators generating additional normal forces through external spring, damping and stabilizer forces. A passenger car is investigated using commercial software.
2014-04-01
Technical Paper
2014-01-0864
Walid Oraby, Mahmoud Atef Aly, Samir El-demerdash, M. El-Nashar
Abstract Integral Control strategy for vehicle chassis systems had been of great interest for vehicle designers in the last decade. This paper represents the interaction of longitudinal control and lateral control. In other words the traction control system and handling control system. Definitely, tire properties are playing a vital role in such interaction as it is responsible for the generated forces in both directions. A seven degrees of freedom half vehicle model is derived and used to investigate this interaction. The vehicle body is represented as a rigid body with three degrees of freedom, lateral and longitudinal, and yaw motions. The other four degrees are the two rotation motion of the front wheel and the rear wheel. This two motions for each wheel are spin motion and the steering motion. The traction controller is designed to modulate engine torque through adjusting the throttle angle of the engine upon utilized adhesion condition at the driving road wheels.
2014-04-01
Technical Paper
2014-01-0617
Sajjad Beigmoradi, Kambiz Jahani, Babak Ravaji
Abstract Efficient function of brake system is considered a crucial stage in the vehicle development process. Heat exchange reduction can decrease the operational condition of braking system. Although the rims patterns have a significant role on vehicle aerodynamics, they can also have effect on air flow around the brake disk. So, selecting a rim is vital from both a safety and an aerodynamic point of view. In this paper the effect of air flow around a brake disk for two different types of rims was studied; a steel casting and an aluminum alloy rim. Numerical simulation was used for this analysis. First, the flow field around brake disk with iron casting rim was investigated at different velocities. Second, the flow field around the same brake disk system with an aluminum alloy rim was modeled at the same velocities. Finally, the effect of rim design on flow pattern over brake disk was compared.
2014-04-01
Technical Paper
2014-01-1783
Quan Zhou, Gangfeng Tan, Xuexun Guo, Zhigang Fang, Bian Gong
Abstract Focusing the vehicle riding safety and global environmental problems, plenty of solutions on vehicle braking systems appeals during the recent period. Criteria and standards set up for commercial vehicles which should have equipped assisted braking systems were established by amounts of governments. Since eddy current retarders plays an important role in the area of assisted braking system, this article presents an energy-recuperation retarder, which is parallel connected with the driveline through a planet gear system. This paper offers a particular Energy-Recuperation Eddy Current Retarder (ERECR) system with a pedal control system and its characteristics is presented, either. Initially, the constitution of the energy-recuperation eddy current retarder system is established whereas the working principle of the energy-recuperation eddy current retarder is presented by modeling the system and simulation.
Viewing 241 to 270 of 10028

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