Browse Topic: Four wheel drive

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Holistic hydraulic designs add more sensors, controls19TOFHP08_078/1/2019
Hydraulic system developers are moving on many different fronts as they strive to improve performance and efficiency. A full-system approach that includes more sensors and advanced controls is helping design teams reduce component counts without sacrificing performance. The multifaceted design challenges of today's equipment are forcing engineers to take a broad view of the vehicle and its systems in order to get the most from valves, electronics, pumps and other equipment. Customer expectations and regulatory requirements are both rising, forcing engineers and planners to examine every element of a design.
Costlow, Terry
Volvo CE sees major efficiency gain from hybrid-electric wheel loader17TOFHP10_1210/1/2017
Volvo Construction Equipment partnered with Waste Management (WM), the California Energy Commission and CALSTART to put its LX1 prototype electric hybrid wheel loader to the test: field test, that is. The company showcased the LX1 at a media event in July at WM's Redwood Landfill in Novato, CA. Made up of 98% new parts, the LX1 prototype series hybrid has a fundamentally new machine design. It incorporates a driveline that consists of electric-drive motors mounted at the wheels, electric-driven hydraulics, a battery energy storage system, a significantly smaller diesel engine and new machine architecture including a new design of the lifting unit.
Shuttleworth, Jennifer
The Dual Phase Twin Synchronous Belt Drive2017-01-17736/5/2017
The dual phase twin synchronous drive has been developed for belt noise reduction. Two identical synchronous belts are arranged parallel side by side with one tooth staggered against other by the half pitch offset. The noise cancellation effect is achieved as one belt tooth engagement coincides with the other belt tooth dis-engagement. A center flange is used as a divider to prevent the belts contacting each other along the axial direction during their entrance and exit of the sprocket. An overall 20 [dBA] noise reduction has been achieved with the dual phase twin belt drive compared to an equal width single belt counterpart. The vibration amplitude of the hub load is also reduced which is directly correlated to the structural borne noise. Comparing to the related dual phase helical tooth belt, the dual phase twin belt is superior in torque carrying capability; and is on par with noise mitigation. The dual phase twin belt has been demonstrated with the automotive transfer case application by four wheel drive SUV, where a conventional metal chain, or Morse Chain, is commonly used. Besides the apparent mass saving, replacing the metal chain with a belt also benefits the environment, as the normally essential chemical lubrication is completely eliminated.
Yuan, Jing
General Motors’ New Reduced Scale Wind Tunnel Center2017-01-15343/28/2017
The General Motors Reduced Scale Wind Tunnel Facility, which came into operation in the fall of 2015, is a new state-of-the-art scale model aerodynamic test facility that expands GM’s test capabilities. The new facility also increases GM’s aerodynamic testing through-put and provides the resources needed to achieve the growing demand for higher fuel economy requirements for next generation of vehicles. The wind tunnel was designed for a nominal model scale of 40%. The nozzle and test section were sized to keep wind tunnel interference effects to a minimum. Flow quality and other wind tunnel performance parameters are on par with or better than the latest industry standards. A 5-belt system with a long center belt and boundary layer suction and blowing system are used to model underbody flow conditions. An overhead probe traverse system is installed in the test section along with a model positioning robot used to move the model in an out of the test section. The facility includes a model shop area and an office section for aero development and CFD engineers. The close proximity to the full size wind tunnel and the Global Design Center support the workflow of the vehicle design and development process.
Tortosa, Nina, Schroeck, David, Nagle, Tony, Flynt, Guy
Development of Integrated Chassis Control for Limit Handling2016-01-16384/5/2016
This paper presents the integrated chassis control(ICC) of four-wheel drive(4WD), electronic stability control(ESC), electronic control suspension(ECS), and active roll stabilizer(ARS) for limit handling. The ICC consists of three layers: 1) a supervisor determines target vehicle states; 2) upper level controller calculates generalized forces; 3) lower level controller, which is contributed in this paper, optimally allocates the generalized force to chassis modules. The lower level controller consists of two integrated parts, 1) longitudinal force control part (4WD/ESC) and 2) vertical force control part (ECS/ARS). The principal concept of both algorithms is optimally utilizing the capability of the each tire by monitoring tire saturation, with tire combined slip. By monitoring tire saturation, 4WD/ESC integrated system minimizes the sum of the tire saturation, and ECS/ARS integrated system minimizes the variance of the tire saturation. However, with only minimizing the sum of tire saturation in 4WD/ESC, the performance of the algorithm is inconsistent against gain and vehicle state, i.e., lateral acceleration and velocity. Thus, the allocation guideline, which guides the control input in the vicinity of the guideline, is designed. Meanwhile, to reduce workload of the 4WD/ESC, the ECS/ARS integrated system generates the additional yaw moment based on relationship between lateral and vertical tire forces. The performance of the algorithm has been investigated via computer simulation. It has been shown that the proposed ICC algorithm effectively keeps stability and maneuverability of the vehicle. In addition, the simulation results show that the 4WD/ESC keeps tire slip within stable region and ECS/ARS reduces yaw rate oscillation.
Joa, Eunhyek, Yi, Kyongsu, Kim, Kilsoo
Design and Development of All Terrain Hybrid Vehicle for Scientific Expedition2016-28-01762/1/2016
The hybrid robot, will be a battery operated four wheel drive vehicle with a rigid chassis for all terrain operation. The vehicle will be suited for various payloads based on applications with geological, atmospheric sensors such as oxygen measurement, glacier thickness measurement, CO2 measurement, thermal properties measurement, salinity, buried object identification at a depth of 8 to 100 m., etc . The vehicle will be remotely controlled through a RF signal which allows it to maneuver up to 5 km. The novelty of the design, is its capability for all terrain and ease of trafficability based on skid steering, self alignment of sensors and vehicle traction in spite of possible inverted conditions and the vehicle can travel from land, snow, water and vice versa. The vehicle can be used in survey at coastline of water bodies, borderlines and can also be extensively used in polar region for studying glacier aging and as advance vehicle for the convoys and polar mapping.
Siva, Rajesh, Janarthanan, C., Muthuvel, P., Kuttikrishnan, Gopkumar, Ramadass, Gidugu, Atmanand, Malayath
Study on the Bending Vibration of a Two-Piece Propeller Shaft for 4WD Driveline2015-01-21746/15/2015
Currently, four wheel drive (4WD) system is widely used in Sports Utility Vehicle (SUV) due to the increasing demand of fuel efficiency and dynamic performance by customers. However, propeller shaft consisting of different universal joints and tubes on 4WD vehicle easily induces low frequency bending vibration. This paper analyzes the characteristics of driveline bending vibration of a 4WD vehicle and provides control methods to reduce the low frequency vibration caused by propeller shaft bending resonances. Firstly, the driveline bending vibration model of the 4WD vehicle is established using FEA method and the natural frequencies are calculated. Secondly, the influence parameters, such as universal joint, relative length of two-piece propeller shaft, and tube diameters, on bending frequencies are analyzed by both FEA analysis and physical testing. Thirdly, the bending vibration responses for several propeller shafts with different lengths and diameters are predicted by unit force input at PTU shaft output. Finally, the control methods to reduce propeller shaft bending vibration are proposed. The analysis results are validated by testing and both reach good consistency.
Xia, Yuanfeng, Pang, Jian, Zhou, Cui, Li, Hongcheng, Li, Wenjuan
Torsional Vibration Analysis of Powertrain and Driveline Using Finite Element Method2015-01-22876/15/2015
Among the lower frequency vehicle NVH problems, booming noise is one of the most concerned issues. One of the most common booming noise sources is the torsional vibration of the powertrain and driveline for rear-wheel drive and four-wheel drive vehicles. The solutions for this problem are either to use a torsional dynamic absorber or to use a lower stiffness clutch. Both solutions require the modal frequency of the torsional vibration mode of the powertrain and driveline. At early design stages, vehicle prototype is not available for measuring this frequency. Analytical method is usually used to calculate this frequency. Currently, mostly used method is the so-called 1D method in which the whole powertrain and driveline are represented by one-dimensionally connected disks (lumped inertia) and shaft (lumped stiffness). However, those lumped parameters are not always available at early design stage. In this paper, a method using finite element models is presented. In this method, all components in the powertrain and driveline are modeled by either three-dimensional solid mesh or two-dimensional shell mesh. The component FE models are connected together to construct the model for the whole powertrain and driveline based on the physical connections between them. The constructed FE model is used for modal analysis by MSC/Nastran. The results of the modal analysis will have the information of the torsional mode. To demonstrate this method, a rear-wheel drive vehicle will be included in the paper as a case study. Results of the modal testing and noise measurements will also be presented.
Deng, Yaqiong, Zhao, Yanjing, Zeng, Xiandi
Integrated Chassis Control for Enhancement of High Speed Cornering Performance2015-01-15684/14/2015
This paper describes an Integrated Chassis Control (ICC) strategy for improving high speed cornering performance by integration of Electronics Stability Control (ESC), Four Wheel Drive (4WD), and Active Roll Control System (ARS). In this study, an analysis of various chassis modules was conducted to prove the control strategies at the limits of handling. The analysis is focused to maximize the longitudinal velocity for minimum lap time and ensure the vehicle lateral stability in cornering. The proposed Integrated Chassis Control algorithm consists of a supervisor, vehicle motion control algorithms, and a coordinator. The supervisor monitors the vehicle status and determines desired vehicle motions such as a desired yaw rate, longitudinal acceleration and desired roll motion. The target longitudinal acceleration is determined based on the driver's intention and vehicle current state to ensure the vehicle lateral stability in high speed maneuvering. The vehicle motion control algorithm calculates a desired longitudinal force, yaw and roll moment for the generation of the desired vehicle motions. In the coordinator, actuator control inputs are coordinated to optimize the driving performance based on proposed strategies. Closed loop simulations of a driver-vehicle-controller system were conducted to evaluate the performance of the proposed control algorithm. The performance of the Integrated Chassis Control has been compared to those of individual chassis control systems such as ESC, 4WD, ARS, and Electronic Control Suspension (ECS). Simulation results show that the proposed ICC algorithm reduces lap time compared to the individual chassis control systems.
Heo, Hyundong, Joa, Eunhyek, Yi, Kyongsu, Kim, Kilsoo
A Mainstream Test Methodology for Developing a Vehicle Equipped with an Electronic Stability Control System2014-01-01304/1/2014
There have been many articles published in the last decade or so concerning the components of an electronic stability control (ESC) system, as well as numerous statistical studies that attempt to predict the effectiveness of such systems relative to crash involvement. The literature however is free from papers that discuss how engineers might develop such systems in order to achieve desired steering, handling, and stability performance. This task is complicated by the fact that stability control systems are very complex and their designs and what they can do have changed considerably over the years. These systems also differ from manufacturer to manufacturer and from vehicle to vehicle in a given maker of automobiles. In terms of ESC hardware, differences can include all the components as well as the addition or absence of roll rate sensors or active steering gears to name a few. Like in the development of passive suspensions and steering systems, a development engineer must take into account the mission of a vehicle. There is no need to tune an ESC system on a two door sports car for off road driving or trailer towing but work may be focused on maximum cornering characteristics whereas a commercial four wheel drive pickup truck will require tuning that accounts for its anticipated load-carrying duty cycle. This paper puts forth a methodology that a vehicle dynamics development engineer might consider when tasked with developing and/or evaluating the stability-control-related steering, handling, and stability characteristics of a given vehicle.
Tandy, Donald F., Beane, Steven, Pascarella, Robert
Powertrain Integration and Controls Development Process for a Parallel Through the Road Plug-in Hybrid Electric Vehicle2014-01-19174/1/2014
The University of Washington Advanced Vehicle Works team has spent the last two years designing and integrating a Parallel Through The Road (PTTR) PHEV drive system into a stock Chevy Malibu as part of the EcoCAR 2 Advanced Vehicle Technology Competition. This paper presents the integration efforts performed throughout year 2 in an effort to produce a 65% “buyoff ready” prototype vehicle. EcoCAR2 challenges 16 universities across North America to reduce the environmental impact of a 2013 Chevrolet Malibu without compromising consumer acceptability. The architecture chosen by the team to address these goals is a PTTR PHEV which provides all-electric operation to displace petroleum usage, four wheel drive mode to improve utility performance for consumers, and an efficient charge-sustaining mode using 20% biodiesel (B20). The PTTR architecture is the lowest cost architecture to provide all of these benefits, and it does so without compromising the safety or performance of the platform.
Crain, Trevor, Wilke, Joshua, Boyer, Brendan, Fayer, Trevor, Fabien, Brian, Reinhall, Per
A Novel Hierarchical Global Chassis Control System for Distributed Electric Vehicles2014-01-00914/1/2014
The current global chassis control (GCC) frequently makes use of decoupled control methods which depend on driving condition partition and simple rule-based vertical force distribution, and are insufficient to obtain optimal vehicle dynamics performance. Therefore, a novel hierarchical global chassis control system for a distributed electric vehicle (DEV), which is equipped with four wheel driving/steering and active suspension systems, is developed in this paper. The control system consists of three layers: in the upper layer, the desired forces/moments based on vehicular driving demands are determined; in the middle layer, a coordinated control method of longitudinal/lateral/vertical tire forces are proposed; in the lower layer, the driving/steering/suspension control is conducted to realize each distributed tire force. As the most outstanding contribution of this paper, a non-convex optimization problem with multiple constraints for coordinated control of longitudinal/lateral/vertical tire forces is solved, in which (1) tire force distribution problem is theoretically concluded as a constrained non-convex optimization problem, (2) a unique objective function that combines the tire workload and the dynamic ratio of the vertical forces is designed to evaluate tire force distribution, (3) 14 constraints including vehicular driving demands, tire friction limitations and actuator natures are involved to bound each tire force reasonably, and (4) an algorithm that combines constrained optimization and feasible region planning is proposed to solve the constrained non-convex optimization problem. Simulation results based on Matlab/Simulink and CarSim show that the proposed hierarchical global chassis control system effectively achieves better vehicle attitude and handling stability during the accelerated double lane change scenario compared with the other GCC methods.
Luo, Yugong, Cao, Kun, Dai, Yifan, Chu, Wenbo, Li, Keqiang
The Regenerative Braking Control Strategy of Four-Wheel-Drive Electric Vehicle Based on Power Generation Efficiency of Motors2013-01-04124/8/2013
Nowadays, the endurance mileage of electric vehicle is commonly short. For the purpose of enhancing the endurance mileage of 4WD electric vehicles, this paper proposes a new control strategy based on the generation efficiency of in-wheel motors. When the brake strength is low, the strategy defines the torque on which the motor has the highest generate efficiency as the upper limit of the braking torque of the front axle. What's more, the proportion of mechanical braking force is reduced. Because of these, the vehicle has a higher generation power. The simulation model is built up by using Matlab/Simulink and CarSim software, and the strategy is simulated under several driving cycles. The result shows that, comparing with the two traditional braking force distribution strategies, the new strategy can obviously improve the regenerative efficiency.
Xu, Wenkai, Zheng, Hongyu, Liu, Zongyu
The Importance of Maximizing Grid Electricity Usage in the Component Selection and Design of a Midsize PHEV2013-01-05484/8/2013
The University of Washington EcoCAR2 team (UWEC2) is currently in the process of building a Plug-in Hybrid Electric Vehicle (PHEV) for the EcoCAR2 Challenge. This competition challenges 15 universities across North America to reduce the environmental impact of a 2013 Chevrolet Malibu without compromising consumer acceptability. In order to be competitive in EcoCAR2, grid electricity is relied on heavily and the use of the Utility Factor method presented in SAE J2841 - Utility Factor Definitions must be used to compare emissions and consumption results with traditional vehicle results. Powertrain simulation in Autonomie was performed to explore many different hybrid architectures. The simulation results were normalized using the Utility Factor method to reach final architecture and component decisions. The architecture chosen by the team to address the competition goals is a Parallel Through The Road (PTTR) PHEV which provides all electric operation to eliminate petroleum usage on short trips, four wheel drive mode to improve utility performance for consumers, and efficient charge-sustaining hybrid operation. The PTTR architecture is the lowest cost architecture to provide all of these benefits, and it does so without compromising the safety performance of the platform. The front powertrain consists of a General Motors (GM) 100kW 1.7L LUD Turbo Diesel internal combustion engine running on B20 as a range extender. On the rear powertrain there is a 150kW peak Remy HVH250 Rear Traction Motor (RTM) mated to a GKN gearbox with a 9.59:1 gear ratio. Powering the rear powertrain is an 18.9 kWh A123 Energy Storage System (ESS). The nominal voltage of the system is 340V. This paper will present the development of the UW EcoCAR2 team's vehicle design, with justification on major decisions coming from a Utility Factor standpoint to explore the importance of using of grid electricity in transportation.
Fayer, Trevor, Crain, Trevor, Fabien, Brian, Reinhall, Per
An Anti-Lock Braking Control Strategy for 4WD Electric Vehicle Based on Variable Structure Control2013-01-07174/8/2013
Based on the four-wheel-drive electric vehicle (4WD EV), a variable structure control (VSC) strategy is designed in this paper for the anti-lock braking control. With nonpeak friction coefficient as target, sign judgment method of switch function in this VSC strategy is improved and a new control algorithm is proposed. The improved VSC strategy is made robust to the parameters of the algorithm and verified by the computer simulation as well as the hard-in-loop test. The results show that the slip rate can be controlled to a point in the stable area near the optimal slip ratio and the control strategy can effectively realize the anti-lock braking control.
Zhu, Hao, Yu, Zhuoping, Xiong, Lu, Zheng, Hui
Development of a Parallel through the Road Plug-In Hybrid Electric Vehicle2012-01-17679/10/2012
The University of Washington Advanced Vehicle Works team is currently in the process of designing Plug-in Hybrid Electric Vehicle (PHEV) for the EcoCAR2 Challenge. This competition challenges 15 universities across North America to reduce the environmental impact of a 2013 Chevrolet Malibu without compromising consumer acceptability. The architecture chosen by the team to address these goals is a Parallel Through The Road (PTTR) PHEV which provides all electric operation to displace petroleum usage, four wheel drive mode to improve utility performance for consumers, and effective charge-sustaining operation. The PTTR architecture is the lowest cost architecture to provide all of these benefits, and it does so without compromising safety performance of the platform. This paper presents the VTS development process, architecture selection process, component selection process and design of a vehicle with particular emphasis on the unique or novel approaches used to solve any design problems.
Fayer, Trevor, Crain, Trevor, Wurden, Richard, Wilke, Joshua, Fabien, Brian
Rollout Deceleration of Modern Passenger Vehicles2012-01-06164/16/2012
Vehicle post-impact travel distances are often available to the accident reconstructionist. Energy dissipated after impact can be significant, and it is often necessary to account for this energy. The deceleration and energy dissipation experienced by a vehicle after a collision is dependent on many variables including tire rolling resistance, engine and drive-train resistance and aerodynamic drag. New technologies that significantly modify the traditional drive train, low rolling resistance tires, and new aerodynamic body designs affect vehicle deceleration, but associated data is not widely available. Roll-out tests were performed in which speed, acceleration and position measurements were made. Vehicles tested were equipped with hybrid (gasoline-electric) and standard engines, CVT (continuously variable transmission), manual and automatic transmissions, and two wheel and four-wheel drive. Results are presented to characterize the effect of vehicle speed, gear, and ignition status (engine on or off). The different measurement methodologies employed are compared for accuracy, repeatability and ease of use. A review of published vehicle decelerations is presented and compared to the data collected in the current series of tests. The applicability of this new deceleration data to a range of vehicles similar to those tested is discussed.
White, Kirsten, Merala, Raymond, Desautels, Daniel, Ellis-Caleo, Tim
A Novel Method of Axle Torque Measurement for Off-Road Vehicles2012-01-03104/16/2012
Most vehicles designed primarily for off-road use - whether for the SUV, military, agricultural or earthmoving industries - employ all wheel drive systems. For off-road conditions where the traction is limited by the deformable nature of the ground, for example, loose track, soil or sand, providing a drive torque to all the wheels is the obvious design solution for maximising the total tractive effort. For military or commercial vehicles, this results in optimum mobility in difficult terrain, whereas for agricultural or earthmoving vehicles it often results in optimum work rates. In order to analyse the performance of off-road vehicles, it is necessary to understand the torque and power flows through the driveline system to each axle or wheel. The research presented in this paper focuses on the use of novel, non-contact torque sensors to measure the driveline torque distribution. The example vehicle is a four wheel drive (4WD) agricultural tractor - but it is proposed that the same measurement techniques could be applied to any off-road vehicle. The torque sensor is a non-contact, bi-directional transducer based on the magnetostrictive principle. The shaft to be measured has a chevron pattern plated on to its surface in copper - and then around this is placed a sensor housing with sets of primary and secondary windings. When a torque is applied to the shaft, the change in magnetic flux of the copper chevrons is sensed in the windings. The benefits of this system include simplicity, reliability, linearity compactness and ease of fitting. These features enabled torque measurements to be made at the input to the main gearbox (engine output torque) and the front and rear driveshafts of the tractor. The driveline measurement system in practice demonstrated substantial improvements over previous systems described in the literature, all of which appear to have been based on strain-gauge type devices. The paper describes the experiences of using this system in field measurements with the tractor operating in high draught force conditions - as is normal for many agricultural tasks. Example results are used to show that the torque and power flows through the driveline are not as straightforward as previous research has suggested - the tractive force vs wheelslip characteristics at the front and rear tyres can cause interactions which result in unanticipated front and rear axle torque distributions.
Guy, Ianto
Soil Stress State Under Loads of Commercial Vehicles2011-01-21739/13/2011
The paper contains experimental results of soil stress state under loading of commercial wheeled vehicles. The measurements were performed with the use of SSTs (Stress State Transducers), which enable to determine soil pressures needed for calculations of stress state at a point: principal stresses and their direction cosines as well as octahedral stresses. A detailed description of the measuring method with an introductory theory of operation of the SST together with some methodology aspects of soil pressure measurements are included. The field tests were conducted on three different soil surfaces: loess, sand and turf as well as on snow surface in winter conditions. For the tests, two vehicles were used: a 5,6T 4x4 truck and a 14T 6x6 truck. The vehicles were driven at constant low speed or at different speeds. Moreover, effects of wheel loading, reduced inflation pressure, drive modes (rolling or driving) were also analyzed. The results are presented partially in a form of stress courses and as numerical data of peak maximum stresses under wheels.
Pytka, Jaroslaw
4WID/4WIS Electric Vehicle Modeling and Simulation of Special Conditions2011-01-21589/13/2011
This paper introduces the characteristics of the 4 wheel independent driving/4 wheel independent steering (4WID/4WIS) electric vehicle (EV). Models of Subsystems and the vehicle are constructed based on Matlab/simulink. The vehicle model allows the inputs of different drive torques and steer angles of four wheels. The dynamic characteristics of drive motors and steer motors are considered, and also it can reflect the vehicle longitudinal dynamics change due to the increase of the mass and inertia of the four wheels. Besides, drive mode selection function that is unique to this type vehicle is involved. Simulations and analyses of crab, oblique driving and zero radius turning which are the special conditions of 4WID/4WIS EV are conducted. The results show that the model can reflect the dynamic response characteristics. The model can be used to the simulation analyses of handling, stability, energy saving and control strategies verification of 4WID/4WIS EVs.
Liu, Jingwen, Zong, Changfu, Ma, Yuqian
Distribution Method of Front/Rear Wheel Side-Slip Angles and Left/Right Motor Torques for Range Extension Control System of Electric Vehicle on Curving Road2011-39-72085/17/2011
In this paper, the range extension control system based on least square method is proposed for electric vehicles with in-wheel motors and front active steering. This proposed method distributes front and rear wheel side-slip angles and driving force difference between left and right motors from lateral force and yaw-moment. The proposed method enables to reduce driving resistance generated from front steering angle. In fact, the mileage per charge is extended up to 200 m/kWh. Simulations and experiments are carried out to confirm the effectiveness of the proposed method.
Sumiya, Hayato, Fujimoto, Hiroshi
The Technology and Economics of In-Wheel Motors2010-01-230710/19/2010
Electric vehicle development is at a crossroads. Consumers want vehicles that offer the same size, performance, range, reliability and cost as their current vehicles. OEMs must make a profit, and the government requires compliance with emissions standards. The result - low volume, compromised vehicles that consumers don't want, with questionable longevity and minimal profitability. In-wheel motor technology offers a solution to these problems; providing power equivalent to ICE alternatives in a package that does not invade chassis, passenger and cargo space. At the same time in-wheel motors can reduce vehicle part count, complexity and cost, feature integrated power electronics, give complete design freedom and the potential for increased regenerative braking (reducing battery size and cost, or increasing range). Together, these advantages create the tipping point for OEM acceptance of in-wheel-motor technology, offering them an immediate opportunity to build larger electric and hybrid vehicles, including full-size sedans and SUVs -vehicles that consumers want and are profitable to manufacture.
Watts, Andy, Vallance, Andrew, Whitehead, Andrew, Hilton, Chris, Fraser, Al
Upgrade of the Volvo Cars Aerodynamic Wind Tunnel2007-01-10434/16/2007
The aerodynamic wind tunnel at Volvo Cars, known as the PVT, was recently upgraded to a moving ground wind tunnel to improve simulation quality. The moving ground simulation system consists of a 5-belt rolling road system (a centre belt and four wheel drive units). Flow simulation has also been improved by a new boundary layer control (BLC) system with a basic suction scoop, large distributed suction areas and aft belt tangential blowing. In addition, the wind tunnel main fan motor has been up-graded from 2.3 MW to 5 MW to provide a wind speed of 250 km/h in the full test section. Previously, 250 km/h was achieved only by installing inserts to reduce the test section area. The present paper provides an outline of the design features, philosophy of the new systems, aerodynamic calibration and commissioning results.
Sternéus, Johan, Walker, Tim, Bender, Trevor
Stochastic Modeling of a Four Wheel Drive Loader Linkage2006-01-349610/31/2006
The manufacturing tolerances of off-highway machine linkages have an impact on linkage position during machine use. A study was undertaken to determine the extent of these tolerances on linkage position for standard machining tolerances of each linkage pin joint for a four wheel drive loader linkage. Linkage positions and distributions for each pin joint are shown in order to determine positional accuracy of the working tool connected to the linkage and impact to the machine loads. It is determined that the affect of the machining tolerances on this linkage have a very minor impact on the linkage position when the linkage is in new condition (before use) and the maximum variation in linkage actuation loads is less than 1% of nominal load.
Hindman, Jahmy, Burton, Richard, Schoenau, Greg
A Data Analysis Approach to Understand the Value of a Damping Treatment for Vehicle Interior Sound2003-01-14095/5/2003
An in-vehicle study was conducted to understand how damping treatments on the floor of a vehicle affect the interior sound in the vehicle. Three differently formulated damping treatments were tested on three similar sport utility vehicles for this purpose. Numerous on-road sound and vibration data were collected under different operating conditions, and were reduced to understand the value of the damping treatment in controlling interior noise caused by powertrain and rolling-tire/road interaction. The paper discusses different data analysis procedures that were used in this study to understand whether there is a damping treatment that performs better than others in spite of variances in test vehicles, and still minimize the adverse influence of other variables that are related to the vehicle performance variation itself.
Polce, Charles T., Saha, Pranab, Groening, James A., Schappert, Ray
An Off-Road Competition Hydraulic Vehicle2002-01-14503/19/2002
A 4-wheel drive off-road vehicle was designed and fabricated using extensive hydraulic technology for the SAE (Society of Automotive Engineers) Mini-Baja competition. The vehicle incorporates an open hydrostatic transmission using a single pump and four independent drive motors. A constant power controller that maintains full engine power to drive the vehicle or stores excess energy in two accumulators controls the pump. Each of the drive motors is independently controlled using a proportional meter-out pressure control valve. The use of pressure control allows the flow to each of the motors to be proportioned based on the dynamics of the vehicle. A CAN bus controller is used in conjunction with a steering sensor to provide differential motor speed control in maneuvering conditions that insures 4-wheel drive availability at all times. Steering of the vehicle is achieved by articulating the chassis using a rotary actuator and multi-motion actuator controlled by the driver. Incorporating these features in the vehicle results in a very small turning radius relative to traditional competition vehicles. The use of the hydrostatic transmission allowed the engine to be moved to the front of the vehicle giving a better weight distribution and making the 4-wheel drive effective throughout the range of the competition. Storing the excess energy in accumulators provided a “power boost” capability beyond the fixed engine power level that could be used to accelerate out of turns or pass on straight-aways. The CAN bus controller allowed the car to be “tuned” to track conditions without the need for extensive hardware changes or modifications.
Labus, Thomas J., Wasielewski, Paul
Development of a New Damping Matrices Identification Method and Its Applications2001-01-14074/30/2001
An experimental method to identify damping characteristics of a dynamic system is reported. The method identifies damping matrices of the equation of motion of the system from measured frequency response functions, each different damping mechanism in a distinct matrix. Related experimental techniques and signal processing issues are discussed. Theoretical validation and error study are conducted by applying the method to a theoretical example. The method is applied experimentally to a thin beam with two different damping characteristics for experimental validation and demonstration of the method. Important advantages of the method over existing methods are explained.
Lee, Joon-Hyun, Kim, J., Grinker, Scott C.
Gear Shift Quality Improvement In Manual Transmissions Using Dynamic Modelling2000-05-01266/12/2000
The importance of the gear shift quality of manual transmissions has increased significantly over the past few years as the refinement of other vehicle systems has increased. The synchroniser is often blamed as the cause of many shift quality issues. This is not always the case. The interaction of the entire selector system from the shift fork to the handball, the driveline and the transmission internals all play a part in the overall shift quality. The dynamic interaction of these systems at a component level is difficult to interpret by traditional test methods and virtually impossible at concept stage. To overcome these difficulties a dynamic model of the entire synchroniser, selector mechanism, driveline and transmission has been created. The model predicts the gearshift quality for a given set of input parameters, which can be correlated against test data. The model can then be used for parameter studies to investigate potential improvements to gearshift quality. The model can also be used at the concept stage to indicate suitable specification for synchroniser geometry, component stiffness, mass and inertia. This paper will present experience of gearshift problems using a dynamic model, the structure of the model and the methodology used.
Christopher Kent, David Kelly
The Last Great Miller: the Four-Wheel-Drive Indy CarR-2446/1/2000
Utilizing an extraordinary historical archive, this book contains more than one hundred photos, as well as the text of over one hundred original letters (many written by Miller himself) about the car's development. The Last Great Miller brings to life the history of this unique model of race car.
Borgeson, Griffith
Improved Customer Satisfaction in Automotive Loudspeakers2000-01-00773/6/2000
This paper shows various techniques used for improving customer satisfaction. The results are judged by independent surveys of customer responses obtained, at least one month after vehicle purchase. The Quality Tracking Survey (QTS) results are based on questions similar to nationally recognized car surveys, and are widely used to determine performance ranking. The vehicle under study was considered the worst performing in this category on initiation of this improvement effort. In less than two years, according to an independent survey, this vehicle finished the best of the group surveyed.
Klacza, Robert E.
Automotive Driveline System Engineering2000-01-14391/15/2000
The trend in the automotive industry to include niche products with 4WD results in high development and investment cost for the manufacturer due to major changes to the platform and new technology. System suppliers for 4WD drivelines can help to reduce these costs significantly by developing “standardised” driveline concepts and taking on the responsibility for the layout, design, manufacture, assembly and validation of the system. A range of traction and handling improving limited slip devices as well as halfshafts and propshafts are available. They need to be integrated into the driveline system which then is being optimised with regard to system function, endurance and NVH.
Trommer, Jörg, Exner, Wolfgang
New Venture Gear 261 Transfer Case - A Robust Manual Shift Transfer Case1999-01-12613/1/1999
The NV 261 part-time four-wheel-drive (4WD) transfer case was designed and developed by New Venture Gear (NVG) for the 1999 General Motor's GMT-800 light duty truck series. A modular system allows two separate models, a light duty (LD) and heavy duty (HD), to be built from one platform. Incorporated in the fully mechanical manual mode shift, two-wheel to four-wheel drive, a high capacity durable dual-cone synchronizer in combination with optimized friction reducing components are used in order to achieve shift effort requirements. Implementation of a fine-pitched chain, sprockets, and the use of magnesium cases achieved requirements for reduced noise levels and weight.
Dolan, Stephen M.
4WD Market Trends in Vehicles & the Adaptations of New Technology in the International Automotive Community1999-01-12643/1/1999
This paper will show the trends in the 4 wheel drive vehicles, technologies, and the move to systems approach rather than the independent supplier approach. The trends show how the transfer case and other drive train components are changing using the latest technology. These changes are making more system adaptations possible. There are three directions that the current changes are moving into. 1) Continue to optimize current designs 2) Redesign with new devices and 3) Design new 4WD systems. Examples of future 4WD designs are Hybrid Electric Vehicles with motors at all four wheels, and CVT's. Specifically this paper will show the latest trends from 1994 to 1998 and some predictions into the future. The focus will be the U.S. Market but some references will be made to the world 4x4 market. Brief references will be made to the basics of traction and directional stability as they relate to the 4WD technology. The structure given in The 4WD Building Block Approach SAE Paper #952643 will be used to understand and predict future 4WD systems.
Williams, Randolph C.
All-Terrain Vehicle With Self-Righting and Pose ControlTBMG-321082/1/1998
A small prototype robotic all-terrain vehicle features a unique drive and suspension system that affords capabilities for self righting, pose control, and enhanced maneuverability for passing over obstacles. The vehicle is designed for exploration of planets and asteroids, and could just as well be used on Earth to carry scientific instruments to remote, hostile, or otherwise inaccessible locations on the ground. The drive and suspension system enable the vehicle to perform such diverse maneuvers as flipping itself over, traveling normal side up or upside down, orienting the main vehicle body in a specified direction in all three dimensions, or setting the main vehicle body down onto the ground, to name a few. Another maneuver enables the vehicle to overcome a common weakness of traditional all-terrain vehicles — a limitation on traction and drive force that makes it difficult or impossible to push wheels over some obstacles: This vehicle can simply lift a wheel onto the top of an obstacle.
A System of Evaluating After Market Four Wheel Drive Suspension Performance97311512/31/1997
This paper describes a way to provide a more precise evaluation of the ride of after market suspension systems for four wheel drive vehicles. It explains the use of a Data Logging System and the Analysis of data retrieved by this system to set guidelines to aid in the development of new after market suspension (shock absorbers, springs, sway bars). The use of Data Logging Systems (used extensively on race cars in recent years) for this area of research will prove to be a valuable tool. A great deal of development time can be saved by utilising such a system.
Waugh, Gregory James
A New Concept and Technology Used in a Powershift Transmission for Off-Highway Vehicles9727509/8/1997
A new powershift transmission concept for specific market segments of backhoe loaders and telescopic boom handlers has been designed, thoroughly lab and field tested and is now in full production. This new transmission is identified as the T16000. The concept is a result of extensive market analysis, customer interviews and study of vehicle performance requirements. OEM requirements in terms of reliability and quality have been considered. New technologies such as electronic modulation for directional clutches and electric/hydraulic modulation of the range clutches have resulted in an excellent shift quality vis-a-vis to application requirements and/or driver preference. A special protection system (mechanical) integrated in the control valve protects the transmission from engaging two clutches at the same time, preventing a drivetrain lock-up. All sensors are integrated in the valve body and are totally sealed according to European Standard IP67 specification. Adaptive control algorithms that consider oil temperature and other parameters that change during the life of the product (e.g. wear) are integrated and assure long term stability of shift quality and comfort.
Pecceu, Hendrik
Atacama Desert Trek: A Planetary Analog Field Experiment9724877/1/1997
Nomad, a planetary-relevant mobile robot, is chartered to traverse 200 kilometers across the Atacama Desert in Chile, exploring a landscape analogous to the surfaces of the Moon and Mars. Operating both autonomously and under the control of operators thousands of kilometers away, Nomad and the Desert Trek address issues of robotic configuration, communications, position estimation and navigation in rugged, natural terrain. The field experiment also serves as a testing ground for remote geological investigation, paving the way for new exploration strategies on Earth and beyond. Finally, by combining safeguarded teleoperation with onboard panoramic visualization and a novel user interface, the Atacama Desert Trek provides the general public an unforgettable interactive experience and its first opportunity to remotely drive an exploratory robot. An unprecedented demonstration, the Atacama Desert Trek sets a new benchmark in high performance robotics operations relevant to terrestrial and planetary exploration.
Whittaker, William Red, Bapna, Deepak, Maimone, Mark W., Rollins, Eric
Determining the Value of Vehicle Attributes Using a PC Based Tool9707632/24/1997
Product engineers and product planners are routinely faced with trade-off decisions involving the cost of adding a product feature or modifying an existing feature versus its added value to the customer. The purpose of this paper is to assess the use of a personal computer (PC) for surveying respondents' willingness to pay (WTP) for four options - two-tone color, 4x4 drive, sporty trim package, and extended cab -- available on the base 1997 Ford F-150 truck. The results show that the respondents' stated WTP reflected the value of the options as determined from their prices and fraction of sales.
Monroe, E. M., Cook, H. E.
FE Analysis, Dynamic Test and Correlation of Vehicle Structures96256810/1/1996
Computer simulation using finite element analysis techniques was used to predict and improve the performance of vehicle components and structures. In order to determine the actual loading and validate the FE model, extensive physical testing which involved data acquisition and analysis was undertaken. The paper shows the application of FE analysis and testing with examples for optimization of an automotive wheel, drive line vibration, car body shell interior acoustics and a railway vehicle structure.
Rao, Ananda, Srinivasulu, B., Bidanov, Alex, Currie, Andrew
Super Olefin Polymer for Material Consolidation of Automotive Interior Plastic Parts9602962/1/1996
A new automotive interior component material, TSOP-5 has been developed by refining the technology utilized to develop TSOP-1, the high modulus and high flow material for bumper covers. This new interior component material has excellent molding capability (MI=30dg/min.) yet still maintains high impact resistance which enables the material to be used in areas such as the dash board as well as trim covers requiring to meet the FMVSS 214, the new side impact regulation or the FMVSS 201, the new soft upper trim regulation.
Kawamura, Nobuya, Nomura, Takao, Nishio, Takeyoshi
Ford Explorer Control Trac 4x4 System95264511/1/1995
PURPOSE - Present the new Control Trac four wheel drive system which is the first application of an interactive four wheel drive in a sport utility vehicle. PROBLEM - The Control Trac system was developed in response to the need for a light weight, space efficient, customer friendly, and full function four wheel drive system. The system was targeted to be fully compatible with on highway and off road usage. CONCLUSION - The Control Trac system is a remarkably user friendly, practical, technologically advanced four wheel drive system; compatible with on highway and off road operation.
McKenzie, Clive A., Rama, Gordon P., Martins, Richard A.
The Gemini Phased Chain System: A New Tool in Automotive Power Transmission9506672/1/1995
Extremely low noise levels at high power densities are achieved with a new inverted tooth silent chain system Two chains of random link design are phased such that the first order and subsequent odd orders of sprocket mesh frequency noise are canceled while remaining even orders are minimized by link randomization Current chain noise reduction practice has applied randomization with a primary emphasis on finer link pitch to control mesh frequency noise As the link pitch becomes finer, however, the chain loses strength and package size must increase to compensate The principle of operation of the new phased chain system is not primarily a function of the chain pitch Therefore, significantly higher power transmission densities can be achieved in the same package without sacrificing noise benefits To achieve the noise cancellation, motive power is transmitted by two chains mounted in such a manner that a specified phased lag exists between them at all times The noise reduction efforts described in this paper were achieved with a phase lag of 180° The new system is readily manufacturable It is made with current processing technology Its first production volume application is in the 1995 Chrysler Corporation LH vehicles
Mott, Phil, Martin, Berthold
Lateral Displacement Joint9407343/1/1994
Development is being undertaken of a new type of flexible drive providing lateral displacement between rotating shafts in an axial length no greater than the lateral displacement. These large displacements are undertaken whilst maintaining full torque, constant velocity and with dynamic stability. Minimal forces are reacted on external bearings. Description is given of the mechanical design and automotive implementation together with an outline of the driving and dynamic loads within the unit during displacement. Application studies are described for incorporation of the unit into a range of vehicles including front wheel drive, four wheel drive, off highway and trucks.
Dowling, J., Allday, E. J.
The Design and Construction of MIRA's Climatic Wind Tunnel93195711/1/1993
Due to customer demand, the features list of motor vehicles for the next century will require manufacturers to design vehicles that not only keep up with exacting legislation changes, but also meet higher specifications combined with reduced product cycle times. This paper outlines the development of MIRA's Climatic Wind Tunnel (CWT) as a commercially sponsored venture with total funding being generated within the Automobile Industry, and the effect that this sponsorship had on the fundamental design parameters. The facility can provide air temperatures from -40°C to +55°C, and humidity from 5% to 95% with wind and road speeds up to 200km/h. Both solar and hot road radiation can be simulated. It can accommodate both 2-wheel and 4-wheel drive vehicles and can absorb up to 300 kW of power at the road wheels. The construction of the £4.5 million CWT project was project managed by MIRA's own Civils and Facility Departments and took 14 months to complete from start to finish. This was a complex project which required continuous cooperation between the building contractors and various mechanical and electrical suppliers during the implementation of the consultants technical specification. The paper concludes by describing the range of tests that can be carried out in the CWT that will allow the industry to build better products at lower costs by providing repeatable, secure, climatic conditions at any time of the year without the need to travel to overseas locations.
Fletcher, D. W.
Vehicle Drawbar Test Characteristics of Electric and Viscous Clutch All Wheel Drive Systems93305211/1/1993
Vehicle drawbar testing was conducted in order to establish the relative performance of all wheel drive electric and viscous clutch transfer case systems. The drawbar tests of a Ford Aerostar system with an electric clutch transfer case are compared to viscous clutch systems in a GM Astro and a Chrysler Grand Cherokee. The empirical test results and theoretical comparison show that the electric clutch transfer case system has a greater amount of torque transfer and its reaction time is faster.
Goddard, Steve
A Four Wheel Drive Transfer Case with Internal VR Motors for Shifting and Clutch Actuation93305311/1/1993
A modular, fully automatic transfer case was designed and developed using electronically controlled inboard electric motors for shifting the high - low range and automatically shifting into four wheel drive for control of torque to the front axle. Compact modular construction was used to minimize weight, to provide for either reduction or overdrive, and for easy adaptation to different transmissions.
Baxter, Ralph W.
Performance of Dyna-Bite Traction System9323909/1/1993
The Dyna-Bite®* traction system, developed by the Omitrac corporation, consists of a series of retractable spades which can be placed over a conventional tractor drive tires to improve traction under varying soil conditions. An initial model of the traction system was tested in 1986 (1)**. The performance of this model was compared with a 2WD tractor equipped with single drive tires and a front wheel assist (FWA) tractor. More recently, an improved model DB3-RM was evaluated at the University of Saskatchewan. The results were compared with an equally ballasted IH 1086 2WD tractor equipped with single and dual drive wheels (2). Tests for both studies were conducted on a wide range of soil moisture conditions under a variety of drawbar pull levels. Both models of the traction system provided significant traction improvements. Initial model of the traction system performed nearly as good as FWA while the later model proved superior to both single and dual wheels.
Wilson, Cameron A., Kushwaha, R. L.
Space Station Freedom Deployable Medical Equipment Design and Development9322177/1/1993
Medical capabilities aboard Space Station Freedom will support rapid emergency response, advanced cardiac and trauma life support, and continuing care during transport back to Earth. The Crew Health Care System (CHeCS) Health Maintenance Facility(HMF) provides deployable medical equipment specifically suited to the peculiarities of this mission. Design and development involve adaptation of terrestrial components for use in space. Versatile packaging and interface approaches and creative innovations account for a unique user population and multiple unusual use environments. This technical paper presents an overview of Space Station Freedom deployable medical equipment design, development, and projected use. The paper describes design status for deployable life support equipment and medical officer, patient, and equipment restraints. The paper further describes user, utility, and physical interfaces, environments including Space Station Freedom resource node and hyperbaric chamber, STS Orbiter middeck, and Assured Crew Return Vehicle (ACRV). Background on developmental processes and activities illustrates a range of considerations for adapting terrestrial equipment and activities to foreign environments. Among the processes discussed are various evaluative techniques involving prototype hardware and medical simulations in various evaluation environments, including mock-ups of SSF elements, parabolic flight simulations, and underwater neutral buoyancy testing. The paper also describes the THEME process (Terrestrial Hardware Engineered for the Environment) for adapting terrestrial components for space applications. CHeCS portable medical equipment development has presented many unique challenges. Crews living and working aboard Space Station Freedom will identify additional needs that may be addressed through adaptation of terrestrial hardware. Current CHeCS hardware development may serve as a model for such adaptation.
Eichstadt, Frank
Collision Speed Estimation Using a Single Normalised Crush Depth-Impact Speed Characteristic9206042/1/1992
Theoretical consideration of the energy absorption properties of structures shows that the specific energy absorption (E/Mk) is related to the normalised crush depth (d/L) and to a stress/density parameter. Examination of the crush characteristics of the car population shows that the mean stress/density parameter of the car population in frontal crush is independent of car size. On this basis regression is carried out which relates (2×E/Mk)½ to normalised crush depth (d/L)⅔ Using data from nine staged frontal car to car collisions this generalised specific energy absorption representation is compared with CRASH 3 and with Prasad's (5) individual car reformulation. It is shown that the accuracy of Delta V prediction with Prasad's individual car reformulation is superior to both the normalised crush depth model proposed here and to CRASH 3, both of which have similar accuracies. A missing vehicle energy estimator, E1×[1+Mk1/Mk2] is examined as is the crush depth energy estimator, E1×[1+d2̄/d1̄]. lt is shown that in conjunction with the normalised frontal crush depth regression they can be applied to frontal and to 90 degree front/side car to car collisions.
Wood, Denis P.
Design of Curved Solar Arrays for Solar-Powered Electric Vehicles9116368/1/1991
Students at Rose-Hulman Institute of Technology have designed, fabricated and efficiently integrated a flat solar array in Rose-Hulman's Solar Phantom solar-powered electric vehicle. The choice of a fixed, flat array was influenced by the simplicity and the cost of manufacturing and the number and cost of photovoltaic cells rather than just the energy collecting ability of the array itself. There are three basic types of solar arrays used for solar-powered electric vehicles: curved arrays, flat arrays, and tracking arrays. Our objective is to present a comparison of the three array types based on the power and size constraints imposed by the solar-powered electric vehicle race rules. Although in selecting the type of array for a solar-powered electric vehicle there are concerns other than the energy collecting capability, such as the vehicle aerodynamics, we consider the type of study we have conducted as a necessary first step in understanding the trade-offs with different array designs. A primer for a transcontinental-class solar-powered electric vehicle solar array design is also presented.
Lebaric, Jovan E., Manche, Alan A.
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