"Quattro"-Drive for Every Day Driving
An essential feature of the Audi Quattro permanent four-wheel drive system is in the inter-axle differential located on the hollow output shaft in the gearbox: the drive is taken from this differential forward to the front differential through the inside of the hollow shaft, and rearward to a propellor shaft driving the rear differential. The major advantages in everyday driving include improved traction and a reduced tendency toward throttle induced changes of attitude. The greater traction allows not only better progress in difficult road conditions; it also gives better acceleration in difficult traffic situations, such as when joining a busy main road. The more easily predictable handling response to throttle changes means that Quattro vehicles have better tracking stability. Altogether, the active safety and "roadability" are considerably improved.
10 KWe Dual-Mode Space Nuclear Power System for Military and Scientific Applications
A 10 KWe dual-mode space power system concept has been identified which is based on INEL's Small Externally-fueled Heat Pipe Thermionic Reactor (SEHPTR) concept. This power system will enhance user capabilities by providing reliable electric power and by providing two propulsion systems; electric power for an arc-jet electric propulsion system and direct thrust by heating hydrogen propellant inside the reactor. The low thrust electric thrusters allow efficient station keeping and long-term maneuvering. The direct thrust capability can provide tens of pounds of thrust at a specific impulse of around 730 seconds for maneuvers that must be performed more rapidly. The direct thrust allows the nuclear power system to move a payload from Low Earth Orbit (LEO) to Geosynchronous Earth Orbit (GEO) in less than one month using approximately half the propellant of a cryogenic chemical stage.
14 Degree-of-Freedom Vehicle Model for Roll Dynamics Study
A vehicle model is an important factor in the development of vehicle control systems. Various vehicle models having different complexities, assumptions, and limitations have been developed and applied to many different vehicle control systems. A 14 DOF vehicle model that includes a roll center as well as non-linear effects due to vehicle roll and pitch angles and unsprung mass inertias, is developed. From this model, the limitations and validity of lower order models which employ different assumptions for simplification of dynamic equations are investigated by analyzing their effect on vehicle roll response through simulation. The possible limitation of the 14 DOF model compared to an actual vehicle is also discussed.
1998/1999 AIAA Foundation Graduate Team Aircraft Design Competition: Super STOL Carrier On-board Delivery Aircraft
The Cardinal is a Super Short Takeoff and Landing (SSTOL) aircraft, which is designed to fulfill the desire for center-city to center-city travel by utilizing river “barges” for short takeoffs and landings to avoid construction of new runways or heliports. In addition, the Cardinal will fulfill the needs of the U.S. Navy for a Carrier On-board Delivery (COD) aircraft to replace the C-2 Greyhound. Design requirements for the Cardinal included a takeoff ground roll of 300 ft, a landing ground roll of 400 ft, cruise at 350 knots with a range of up to 1500 nm with reserves, payload of 24 passengers and baggage for a commercial version or a military version with a 10,000 lb payload, capable of carrying two GE F110 engines for the F-14D, and a spot factor requirement of 60 feet by 29 feet.
1D Tire Model Parameter Synthesis for Vehicle Handling Targets Assessment “A Strategy of Optimization and Evaluation of Tire Math’s”
Handling performance of a vehicle is a key characteristic determining the response of vehicle under different operating scenarios. An insight into these vehicle-handling characteristics at early stage can be extremely useful in the design and development process. Tire characterization and tuning is important and mandatory to scrutinize each functional and individual parameter of tire. Tire force and moment data is having a significant effect in vehicle handling. Segregation of tire parameter, which is contributing vehicle-handling performance, helps to identify and perform optimization for improvisation. The main objective of this study is development and integration optimized 1D tire model into multibody dynamics model of the vehicle to observe various vehicle compliances towards its handling performance target.
3 Wet Technology - A Novel Approach for Greener, Efficient, Smart Practice in Automotive Paint Application
The upcoming latest 3-wet Technology is the most ideal design for a Green field project as well as for a brown field facility which provides the best of both worlds. The foremost take away for a brown field project emanates from this technology which demands a smaller foot prints & hence could accommodates a capacity higher than what was perceived during the green field project planning thus saving millions of dollar of investment & giving that extra capacity which today the BRIC countries are thriving for. Apart from making the ideal investment choice, 3 Wet Technology provides impetus to business case in terms of reduction of VOC emission, Energy consumption, Material and labor cost and gaining on Green Environment front as well as leading to smart and Efficient-Paint-Process. The paper depicts the journey of roll out of 3-Wet process in Ford India and creating the bench mark in terms of product quality and process standards and manufacturing practices.
3-D Numerical Analysis Investigating Distribution of Contact Pressures for a Number of Cylindrical Bearing Axial Profiles When Placed Under Radial Load Conditions
Increased torque values passing from engine to transmission have, increasingly become a problem regarding shaft misalignment. Engineers are restricted with regard to applying ISO standards when investigating bearing life cycles as they tend only to cover normal [radial thrust] load conditions. Depending on the application, the need has arisen for numerical models to determine reduction in normal life cycles due to abnormal running conditions. The Simulia Finite Element package Abaqus v6.7 provides trends in the deformations, contact pressures and their respective distribution. It was found the most efficient profile, with regards to a uniform contact pressure, under both radial and misaligned conditions is the toroidal profile.
3-D Numerical Study of Effect of Injection Parameters Upon the Uniformity of Ammonia in Urea-SCR
Nowadays, due to the stringent engine emission norms, an efficient technique is required to reduce oxides of nitrogen (NOx) from automobiles especially from the lean burn engines. Selective Catalytic Reduction (SCR) is found to be an efficient after treatment method used to reduce oxides of nitrogen (NOx) from the exhaust. However, for light duty vehicles, because of the limited size of the catalysts, ammonia slip nullifies its advantages. Lack of uniformity of ammonia at the SCR monolith entrance causes ammonia slip. This study addresses the effect of injection parameters, location of injector and shape of injector upon the flow parameters, exhaust gas temperature and flow rate. The results obtained from this study provide useful guidelines for optimizing the injection parameters to avoid the ammonia slip. The evaporation of Urea Water Solution (UWS) is also investigated.
4-DOF Vehicle Ride Model
Ride quality is one of the most important criteria by which people judge the design of a car. At the most basic level, ride isolation properties are investigated using a quarter vehicle model. But the input from road roughness would excite not only bounce motions, but also pitch motions. Understanding the pitch and bounce motions is essential because it is their combination that determines the vertical and longitudinal vibrations at any point on the vehicle . In this paper, a 4-degree-of-freedom (4-DOF) Vehicle Ride Model, which is shown in Figure 1, is used to investigate the effect on the ride quality of the dynamic index in pitch, mass ratio, weight distribution and flat ride tuning. A Lagrange equation is used to derive the equations of motion. A state-space formulation is obtained by using state variables. From these, the characteristic equation, natural frequency and damping ratio are obtained.
4WS Technology and the Prospects for Improvement of Vehicle Dynamics
FOUR-WHEEL STEERING (4WS) is beginning to find widespread use as a new approach to improving vehicle dynamics, especially in the medium and high speed ranges. Steering the rear wheels in the same phase as the front wheels enhances vehicle stability. Four-wheel steering systems have an even greater potential to improve stability and steering response through suitable control over the transient characteristics of the rear wheel steer angle. This paper traces the course of Nissan research and development work on four-wheel steering and the evolution of Nissan's HICAS (4WS) technology. It also describes research activities under way on vehicle dynamics using a newly developed Simulator Vehicle, equipped with a front and rear angle transient control system which makes it possible to vary the dynamic characteristics of the vehicle instantaneously and at will while driving.
6 DOF Bench Test on a New Active Kinematics Rear Suspension for Functional Development
To optimize the tyre contact patch in a sports car, Ferrari has developed an active camber and toe (ACT) system comprising of 4 actuators for the rear axle. This complex and completely new system is difficult to model accurately and for this reason, it was decided to combine a physical prototype with a full vehicle model to carry out the functional tests. The method of combining a virtual model with a physical test is known as hybrid simulation. This functional testing of both the actuators and the vehicle dynamics logic will be performed on an MTS 6DOF bench test prior to physical track testing on a prototype vehicle using Ferrari facility in Maranello, Italy. In support of this functional testing, we will use hybrid simulation techniques with software and methods specifically developed. The planned hybrid test system described in the paper will allow dynamic coupling between the physical bench test and a modified full vehicle simulation model.
6DOF RTS Drive File Development Technique for Solid-Axle-Type Rear Suspensions Instrumented for 4DOF Applications
The MTS 329LT six degree-of-freedom road test simulator (6DOF RTS) provides additional controls for camber and steer moments resulting in more realistic simulation results compared with results for a 4DOF RTS. However, the 6DOF RTS requires that additional transducers be installed on the data acquisition vehicle to provide the road load information necessary to control these additional moments. Occasionally, road load data available for drive file development may not include the necessary information for controlling steer and camber moments (typically for 4DOF applications). Under such circumstances, it is still possible to develop drive files for solid-axle-type rear suspensions. A technique used to accomplish this task is presented in this paper.
A 2000 Ton Crawler/Transporter for Operation in Prudhoe Bay, Alaska
Recently designed and fabricated in Kennewick, Washington, a pair of 2000 ton capacity crawler/transporters has been used in moving refinery modules to permanent installations on Alaska's North Slope. Vehicle design features include four corner chain-driven, track driving sprockets (tumblers), resilient track roller suspensions, elevating load platform (hereinafter “bolsters”), dynamic braking, diesel/torque converter power, automatic lubrication and electro-pneumatic controls. Four independent power units provide 14 00 horse-power per crawler and over two million pounds of drawbar pull at converter stall. Weighing 300 tons, the pin-connected crawler dissembles for highway transport into loads of under 95,000 pounds.
A 2D Model for Tractor Tire-Soil Interaction: Evaluation of the Maximum Traction Force and Comparison with Experimental Results
The paper investigates the interaction between soil and tractor tires through a 2D numerical model. The tire is schematized as a rigid ring presenting a series of rigid tread bars on the external circumference. The outer profile of the tire is divided into a series of elements, each one able to exchange a normal and a tangential contact force with the ground. A 2D soil model was developed to compute the forces at the ground-tire interface: the normal force is determined on the basis of the compression of the soil generated by the sinking of the tire. The soil is modeled through a layer of springs characterized by two different stiffness for the loading (lower stiffness) and unloading (higher stiffness) condition. This scheme allows to introduce a memory effect on the soil which results stiffer and keeps a residual sinking after the passage of the tire. The normal contact force determines the maximum value of tangential force provided before the soil fails.
A 3-Shaft versus a 2-Shaft Cycle in Automotive Gas Turbines
A 3-shaft cycle turbine with a twin-spool compressor system is compared to a 2-shaft cycle with a variable geometry power turbine. Operating in a heavy commercial vehicle, the following engine parameters are considered: specific output power, fuel consumption, engine response, torque characteristics, and engine braking capability. The 3-shaft cycle showed an average improvement of 5% in sfc, a stall torque ratioof 3.8 versus 2.65 for the 2-shaft cycle, a potential increase in engine braking capability, and engine response consistent with the 2-shaft cycle.
A 3D Semi-Empirical On-Road Transient Tire Model
To realistically predict the dynamics of a vehicle, the forces and moments in the contact patch must be accurately computed. A two-dimensional semi-empirical transient tire model was previously developed in the Advanced Vehicle Dynamics Lab (AVDL) at Virginia Tech, and extended the capabilities of the steady-state tire model also developed at AVDL. In this paper, a three-dimensional semi-empirical transient tire model is presented. The tire structure is modeled by an elastic ring supported on a spring and damper system. The elastic ring represents the belt ring and the spring and damper system represents the sidewall and the tread element. The analysis of the deformation of the tire structure with camber angle is performed on a flat surface to obtain the geometry of the contact patch and the normal pressure distribution. The forces and the moments are formulated using empirical data and based on theoretical mechanics.
A 6 Sigma Framework for the Design of Flatfish Type Autonomous Underwater Vehicle (AUV)
Hydrodynamic parameters play a major role in the dynamics and control of Autonomous Underwater Vehicles (AUV). The performance of an AUV is dependent on the parameter variations and a proper understanding of these parametric influences is essential for the design, modelling and control of high performance AUVs. In this paper, a six sigma framework for the sensitivity analysis of a flatfish type AUV is presented. Robust design techniques such as Taguchi’s design method and statistical analysis tools such as Pareto-ANOVA, and ANOVA are used to identify the hydrodynamic parameters influencing the dynamic performance of an AUV. In the initial study, it is found that when the vehicle commanded in forward direction, it is in bow down configuration which is unacceptable for AUV motion. This is because of the vehicle buoyancy and shape of the vehicle. So the sensitivity analysis of pitch angle variation is studied by using robust design techniques.
A Biodynamic Model for the Assessment of Human Operator Performance under Vibration Environment
A combined biodynamic and vehicle model is used to assess the vibration and performance of a human operator performing driving and other tasks. The other tasks include reaching, pointing and tracking by the driver and/or passenger. This analysis requires the coordinated use of separate and mature software programs for anthropometrics, vehicle dynamics, biodynamics, and systems analysis. The total package is called AVB-DYN, an acronym for Anthropometrics, Vehicle and Bio-DYNamics. The biodynamic component of AVB-DYN is described, and then compared with an experiment that studied human operator in-vehicle reaching performance using the U.S. Army TACOM Ride Motion Simulator.
A CAE Study on Side Doors Inner Panel Deflection under Glass Stall Up Forces
Not only well-functioning, but also the way operating everyday items "feel", gauges costumer perception of an automobile robustness. To prevent costumer dissatisfaction with door trim panel movement when operating power windows, deflections must be kept small. Deflections of inner panel are seen through trim panel and are responsible for giving a flimsy idea of the door. In this paper, inner panel movement for a fully stamped door in full glass stall up position is analyzed. Through CAE analyses, inner panel behavior was compared, considering different types of reinforcement for belt region.