Browse Topic: Rear wheel drive

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An Accurate Analysis Method to Calculate Planetary Gear Set Load Sharing under Non-Torque Load 2022-01-078903/29/2022
Given their high-power density, large range of speed change, and reputation of being quieter than counter-shaft gear sets, planetary gear sets (PGS) have advantages to be applied in electric vehicle (EV) applications. Typical rear wheel drive automatic transmissions have only PGS in gearbox, and power is transferred by torque. Most electric drive units (EDU) equipped PGS are like a simplified front wheel drive automatic transmission. PGS is coupled with counter-shaft gear sets normally at planet carrier which has two functions: original planet pinion carrying and additional transfer gear mounting. The latter brings in non-torque power in PGS through the carrier. This condition hasn’t obtained enough attention by automotive gear researchers regarding to PGS load sharing calculation. Excluding non-torque load here causes underestimating gear and bearing uneven loads in both magnitude and variation. In extreme conditions, undersized parts would miss demanding durability requirements. One
Ma, Qinglong, Black, Derrick
Technical Paper
Development of Innovative Dynamic Torque Vectoring AWD System2019-01-033204/02/2019
This paper describes the development of an innovative AWD system called Dynamic Torque Vectoring AWD for all-wheel drive (AWD) vehicles based on a front-wheel drive configuration. The Dynamic Torque Vectoring AWD system helps to achieve high levels of both dynamic performance and fuel efficiency. Significant fuel economy savings are achieved by using a new compact disconnection mechanism at the transfer and rear units, which prevents any unnecessary rotation of the propeller shaft. In addition, the system is also capable of independently distributing torque to the rear wheels by utilizing electronically controlled couplings on the left and right sides of the rear differential. This greatly enhances both on-road cornering performance and off-road driving performance.
Horie, Ryota, Yuasa, Ryohei
Technical Paper
2020 Ford Explorer: Knockout styling surrounds all-new engineering19AUTP08_2001/01/2019
Already America's all-time best-selling SUV, the all-new 2020 Ford Explorer is cast on an entirely new global rear-wheel-drive (RWD) architecture and boasts the first Ford application of its new modular hybrid transmission (MHT). The lighter and stronger architecture underpins the broadest Explorer lineup yet, featuring a new hybrid, an ST model, more powerful EcoBoost powertrains, all-10-speed gearboxes and a host of new safety/convenience tech. With new styling that is razor sharp, consumers would have likely flocked to it regardless. The biggest news for the 2020 Explorer is the new global RWD architecture, with the Explorer being the first application for Ford (Lincoln has already debuted its version with the all-new Aviator). “When you start all-new, the exciting part is you get to work on not only upping the game, but you get to listen to feedback on the prior product, its shortcomings or opportunities,” explained Scott Slimak, the vehicle engineering manager on the new Explorer
Seredynski, Paul
Magazine Article
Cadillac pulls the wraps off two new V-Series sedans19AUTP08_1901/01/2019
Cadillac has added two more sedans to its V-Series performance lineup, the 2020 CT4-V and CT5-V. The CT4-V will square off against established C-segment players such as the BMW 3-Series and Mercedes-Benz C-Class, along with Hyundai's new Genesis G70. The CT5-V will compete with the BMW 5-Series and Audi A6. The two new 4-door sedans join the larger 2019 CT6-V sedan in the V-Series stable, though the company noted that the series is evolving to be less focused on hard-core, track-worthy machines, and more about sporty and comfortable daily drivers. “We are inviting even more customers into the V-Series family,” said Brandon Vivian, Cadillac executive chief engineer, “by adding a new level of elevated performance between our Sport models and the ultimate, high-performance track capability that the V-Series has grown to represent.”
Seredynski, Paul
Magazine Article
Porsche reveals eighth-generation of fabled 91119AUTP01_1501/01/2019
Regularly updating and evolving the Porsche 911's aesthetic signature might seem an impossible task. But more than half a century after its birth, the unveiling of the eighth-generation at the 2018 L.A. Auto Show demonstrated that it is in fact still a totally possible art-with design boss Michael Mauer the chief artist. Designated in-house as the 992 series and slightly larger than the outgoing 991, it is launched in rear-wheel-drive and all-wheel-drive forms-Carrera S and Carrera 4S-and now only in the wide-body width previously used for the Carrera 4 GT3 and GTS, instead of two body widths. Across the nose, the new 911 is 45 mm (1.8 in) wider than the outgoing version, a figure some 911 purists may look at askance, as growth in recent years has already been considerable.
Birch, Stuart
Magazine Article
Ford details more platform consolidation18AUTP09_0709/01/2018
Ford said it plans to merge today's nine global platforms to five flexible vehicle architectures with a strong emphasis on sharing modules. The automaker's revised product development process is predicted to push down the average age of its vehicles from the current 5.7 years to 3.3 years in 2020. One twist is that as new Ford products reach global markets faster, engineers won't be devoting much time to reinventing vehicle sub-system modules.
Buchholz, Kami
Magazine Article
All-Wheel Drive Systems ClassificationJ1952_201804 (Current)04/18/2018
In this SAE Recommended Practice, attention will be given to passenger cars and light trucks (through Class III).
Drivetrain Standards Committee
Recommended Practice
WHAT WE'RE DRIVING2018 Volvo XC60 T8 Inscription17AUTP11_1411/01/2017
No, Volvo hasn't stuffed its old V8 into the new XC60, but that's what the T8 nameplate of this new plug-in hybrid SUV might imply. Confused? You're not alone. Here, T8 is Swedish engineering code for the union of combustion-engine and electric power, the ICE being a 313-hp (233-kW) turbocharged-and-supercharged 2.0-L four, paired with a 87-hp AC motor to drive the rear wheels. In between is a 46-hp (36-kW) e-motor, 8-speed transaxle and a 10.4-kW·h battery pack tucked into the center tunnel.
Magazine Article
Torsional Vibration Analysis of the Driveline on Light Weight Rear Wheel Drive Vehicle2017-26-021901/10/2017
Globally the customers are demanding more powerful yet silent vehicles to enhance their daily commuting and goods transportation needs. The current trend in the design is to enhance the engine power without major change in the physical configurations of the engine systems. Increasing the power and torque of the powertrain will have an undesirable and adverse effect on NVH levels. In this research work, a light weight rear wheel drive vehicle was investigated from torsional vibration perspective. The vehicle is powered by a two cylinder engine with turbo charger. The power and torque of the vehicle was increased approximately two times with the help of turbocharger which resulted in increasing the powertrain torsional vibration. This increased vibration was further amplified through inevitable driveline resonances which causes severe vibration at the passenger seat location and steering. Also, the noise levels are above the comfortable zone. Operational deflection shapes analysis and
Moorthy, S Nataraja, Rao, Manchi, Raghavendran, Prasath
Technical Paper
Ferrari's CTO details patented torque-vectoring AWD with rear-wheel steer16AUTP04_0704/01/2016
At first, reading the words “Ferrari” and “all-wheel drive” (AWD) seem as compatible as “oil” and “water,” but with the company's original FF entering its fifth year of production, the Maranello engineers decided it was time for its unique AWD system to get an update by incorporating a new, patented torque-vectoring capability and rear-wheel steering. The first Ferrari to feature this integrated capability is the new GTC4 Lusso, a nameplate that conjures both the GTC and Lusso classics, with the ‘4’ denoting not the number of driven wheels but the seating capacity.
Adcock, Ian
Magazine Article
Experimental Investigation of Effect of Driveline Torsional Fluctuations on Overall NVH Performance of the Vehicle2015-01-219206/15/2015
Meeting various customer(s) requirements with the given automotive product portfolio within the stipulated time period is a challenge. Design of product configuration matrix is an intelligent task and it requires information about vehicle performance for different configurations which helps in deciding the level of new development. Most often the situation arises, particularly in the field of NVH, to strike the right balance between engine power and structural parameters of the body. The sensitivity of engine power on the overall NVH behavior is the key information necessary to take major business decisions. In this paper, the effect of change in torsional fluctuation of the engine on the NVH behavior of the rear wheel drive vehicle is experimentally studied. The torsional fluctuation of the driveline is given as an input with the help of an electric motor to the existing test vehicle at its differential end and the current NVH levels are measured. A test rig is built to change the
Rao, Manchi Venkateswara, Frank, Jos, Raghavendran, Prasath
Technical Paper
Experimental Investigation of Power Hop in Passenger Cars2015-01-218506/15/2015
In this paper the power hop phenomenon is analyzed and important influencing factors are investigated. The results of driving tests on various road surfaces with different types of cars with longitudinal and transversal mounted engines as well as with front and rear wheel drive are presented. In order to understand and quantify the power hop effect the rotational speed of the individual wheels and the engine are measured. Additionally, the drive shaft torque, the engine movement in its bearings and the vertical deflection of the wheel with respect to the chassis are determined to get detailed knowledge about physical dependencies. It is shown that the rotational speed of the driven wheels is not a sufficient indicator to assess the occurrence of power hop by measurements. Alternatively, the measured longitudinal acceleration at the seat rail provides a good quantification. Nevertheless a detailed analysis of the rotational speed of the driven wheels points out great variations of the
Eicke, Simon, Zemke, Steffen, Trabelsi, Ahmed, Dagen, Matthias, Ortmaier, Tobias
Technical Paper
All-Wheel Drive Systems ClassificationJ1952_201310 (Historical)10/29/2013
In this SAE Recommended Practice, attention will be given to passenger cars and light trucks (through Class III).
Drivetrain Standards Committee
Recommended Practice
The Development of FR-Based 4WD Multi-Link Suspension2013-01-123504/08/2013
In this paper FR (Front Engine, Rear wheel Drive) based 4WD 5-link independent suspension systems are introduced which are developed for low friction road stability in the winter. The arrangement of the lower control arm of the newly developed suspensions has been changed in order to correspond to 4WD layout. And basic performance is satisfied due to the addition of the driveline. Also NVH (Noise, Vibration and Harshness) performance has improved, to enhance the comfort of the vehicle
Jung, DaeWoo, Lee, Jae Kil, Lee, Byung-Kyu, Kim, Seon Pyung
Technical Paper
Integrating In-Wheel Motors into Vehicles - Real-World Experiences2012-01-103704/16/2012
Compact direct drive in-wheel motors with integrated inverters, control and brakes offer a number of distinct advantages compared to conventional electric drive systems. The most obvious being that the drivetrain is now packaged within the wheel freeing up space elsewhere, in addition many driveline components and their associated losses are eliminated and the vehicle efficiency, response and handling can be improved. In new vehicle applications this allows complete freedom for designers to optimize the vehicle layout, have more usable space inside the vehicle body and enables revolutionary vehicle concepts (which will become more important as road space becomes scarce and taxation measures migrate towards vehicle size). In retrofit applications the compact package allows an electric drive to be added to any existing vehicle without requiring any significant disruption to the vehicle platform to keep integration costs down. This represents an opportunity for OEM's to hybridize their
Watts, Andy, Vallance, Andrew, Fraser, Al, Whitehead, Andrew, Hilton, Christopher, Monkhouse, Helen, Barrie-Smith, John, George, Sunoj, Ellims, Michael
Journal Article
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
Watts, Andy, Vallance, Andrew, Whitehead, Andrew, Hilton, Chris, Fraser, Al
Journal Article
The Technology and Economics of In-Wheel Motors2010-01-2307-TEST-REC10/19/2010
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
Watts, Andy, Vallance, Andrew, Whitehead, Andrew, Hilton, Chris, Fraser, Al
Journal Article
Effect of Different Magnesium Powertrain Alloys on the High Pressure Die Casting Characteristics of an Automatic Transmission Case2010-01-040904/12/2010
The main objective of this paper is to demonstrate how flow and solidification simulation were used in the development of a new gating system design for three different magnesium alloys; and to determine the relative castability of each alloy based on casting trials. Prototype tooling for an existing 3-slide rear wheel drive automatic transmission case designed for aluminum A380 was provided by General Motors. Flow and solidification simulation were performed using Magmasoft on the existing runner system design using A380 (baseline), AE44, MRI153M and MRI230D. Based on the filling results, new designs were developed at Meridian for the magnesium alloys. Subsequent modeling was performed to verify the new design and the changes were incorporated into the prototype tool. Casting trials were conducted with the three magnesium alloys and the relative castability was evaluated. The conclusion of the study was that all three alloys were castable; however, there were significant differences
Jekl, John, Berkmortel, Richard D., Armstrong, Paula
Technical Paper
Vehicle Handling and Control Following Front Ball Joint Failure2008-01-017104/14/2008
Following many accidents, one of the involved vehicles is found with partial or total separation of one of its wheels. In many such cases, forensic evidence on the wheel, and/or on some surface struck by the wheel, provide direct evidence that the wheel separation resulted from the impact. However, in some cases such direct evidence is not as obvious or cannot be identified. In those cases, it is often asserted that before the accident occurred one of the involved vehicles might have undergone a sudden loss of control as a result of a spontaneous partial or total wheel separation. This paper examines the response of rear wheel drive vehicles when there is a failure involving a ball joint on the front suspension as the vehicle is traveling along a roadway. The design of the front suspension is analyzed to determine the expected effects of such failure on the wheel geometry and on the interaction between the tires and the pavement. Next some case studies of accidents involving wheel loss
Dunn, Ashley L., Tanner, C. Brian, Stansifer, Rickey L., Doyle, Sean A., Guenther, Dennis A.
Technical Paper
Studying the Effects of Lapping Process on Hypoid Gears Surface Finish and Transmission Errors2007-01-222905/15/2007
There are several geometric and working parameters, besides offset, that have minor effects on hypoid gears efficiency (i.e. spiral angle, pressure angle, lubricant type & temperature, surface finish, etc.). Some theoretical analyses of mechanical efficiency of hypoid gears show that surface finish has considerable effect on hypoid gear efficiency. This is due to a high sliding to rolling ratio in these types of gears. In this paper, a study on measuring of surface finish of both ring gear and pinion will be presented. Moreover, the effects of lapping on surface finish will be discussed. Using an accurate form-measuring machine, surface finish measurements were done on several experimentally produced hypoid gear pairs1. Despite the fact that lapping is expected to improve the surface finish, measurement results show that ring gear's surface finish becomes worse (roughness increased) after lapping while no consistent results for pinion surface finish were observed. However, it will be
Masseth, Jack, Kolivand, Mohsen, Blancke, Harry, Wright, Ned
Technical Paper
Hybrid System Development for High-Performance All Wheel Drive Vehicle2007-01-029604/16/2007
The original Toyota Hybrid System (THS) was installed in the Prius and was introduced in 1997 as the world's first mass-produced hybrid passenger car. Since then, THS has been continuously improved. In 2003 THS-II (marketed as Hybrid Synergy Drive [HSD]), was installed in a new larger Prius. In 2006 HSD was installed in a Rear Wheel Drive Vehicle: the LEXUS GS450h. This system achieved both 4.5-liter class power performance and compact class fuel economy with outstanding emissions performance. In 2007, this system is expanded to a mechanical all-wheel-drive(AWD) in the LEXUS LS600hL(with new V8 engine). This paper will explain this hybrid system which achieved both V12 class power performance and mid-size class fuel economy, while meeting the most stringent emission standard SULEV as a full-size vehicle.
Ueoka, Kiyoshiro, Mashiki, Zenichiro, Maruyama, Kenya, Ito, Takeshi, Ito, Masatoshi, Tomura, Shuji
Technical Paper
Statistical Relationship between Corner Weight and Spindle Load2007-01-134604/16/2007
It is important to obtain durability loads at early design stage when no representative vehicle is available. Without road load data acquisition, durability loads have to be derived from mathematical modeling or approximation of spindle loads being acquired previously. Spindle load scaling by corner weight is a quick method for load estimation. No study has been found reporting statistical or theoretical relationship between corner weight and load. Current study presents the statistical relationship between corner weight and measured spindle load. Thirty-one sets of measured spindle load data are studied. These data sets include heavy duty trucks, SUV, minivan, family passenger cars, and small cars. The range of corner weight at left front wheel is between 5430 N and 12479 N. Considering all spindles, there is a strong statistical relationship between vertical spindle load and corner weight with R-square greater than 0.7; there is also a moderate statistical relationship between
Cao, Cheng, Medepalli, Sudhakar
Technical Paper
Friction Coefficient on Snowy and Icy Surfaces of Pneumatic Tires Fitted with or without Anti-Skid Devices2006-01-056004/03/2006
The dynamic performances respectively of a front- and a rear wheel drive car on icy and snowy surfaces has been assessed. Winter pneumatic tires, new anti-slip wheelsocks, and snow chains were tested. The three accelerations and the three angular velocities at the centre of gravity were measured, together with the angular speeds of all axles. The maximum traction force was also measured. Proper maneuvers to investigate both longitudinal and lateral vehicle dynamic behaviour have been performed and a complete analysis of the collected data is presented. The results confirmed the observation that snow chains allow always the best performances on both icy and snowy surfaces.
Previati, Giorgio, Gobbi, Massimiliano, Mastinu, Giampiero
Technical Paper
Lightweight Construction Due to Thermoplastic Foams as Exemplified in an Instrument-Panel Support2006-01-140404/03/2006
The driving behaviour of an automobile is strongly influenced by the weight distribution over the axles. Since all BMW vehicles are rear wheel drive, there is a permanent challenge to reduce the weight of the front of the vehicle. As the instrument panel is found in this relevant area, it is the object of consistent endeavours to save weight. The instrument panel carrier, weighing 3.5 to 4Kg, has the largest proportion of the total weight of the part. Since the end of the 1980’s BMW has been using complete solutions in plastic that are developed to be weight optimized. At the start of 2000 BMW set the goal of decreasing the weight of the instrument panel by a further 20%, while at the same time satisfying all demands placed on the parts. This paper describes the development of a new injection moulding technology, designed to reach the aforementioned goals.
Melzig, Joachim, Lehner, Martin
Technical Paper
Evaluating The Rolling Contact Fatigue Properties Of Surface Densified PM Gears2006-01-039504/03/2006
Surface densification technology allows powdered metal (PM) manufacturing methods to be considered for use in highly stressed product groups such as automotive transmission gears. The paper shows that rolling contact fatigue performance is defined by the interaction of the applied subsurface shear stress profile and the material shear fatigue strength profile. Previous work has shown that surface densified PM gears can provide rolling contact fatigue durability which is at least equivalent to that of wrought steel gears. In respect to the provision of appropriate rolling contact fatigue design data, it is shown that cylinder based test parameters need to be diligently selected, reference in particular needs to be made to actual automotive transmission gear geometrical features, and to the microstructure of the proposed material. It is shown that in the application of cylinder test data to actual components, the maximum surface compressive stress, the peak shear stress and the depth of
Lawcock, Roger
Technical Paper
Getting validationAUTOAPR06_1204/01/2006
OEMs are developing tools so that engineers from around the world can validate vehicles for regulations conformity and other objective and subjective aspects. In the late 1990s, the time frame for Chrysler Group engineers to evaluate 200,000 computer-generated elements typically consumed four or five days. With advancements in computing power, a computer-aided engineering (CAE) analysis of a particular subject now takes about 36 h and covers about one million elements. The ever-closer correlation between the virtual and real worlds-enabled in large part by the amount of detail in math models-is reducing the need for physical vehicle testing. “We're in a phase where we're getting close to eliminating all physical prototypes for development work,” said Ram Bhandarkar, Supervisor of Durability Start of Production and Analysis Methods for Chrysler Group's Advance Vehicle Engineering.
Buchholz, Kami
Magazine Article
Asymmetric Gear Noise Sidebands and Application to Planetary Gear Noise Reduction2005-01-246205/16/2005
Asymmetric sidebands of gear noise are frequently observed with a planetary gear set, and are different from typical sidebands that are symmetrical around the gear mesh order (or mesh frequency). The asymmetric sidebands are found to be caused by phase differences between the different mesh points. The sidebands' locations can be calculated with knowledge of the gear set parameters. In this paper, a numerical simulation is used to predict the sidebands in a 4-speed automatic transmission. An experimental test verifies the theoretical prediction. Finally an application is described to show how to use the theory for gear noise reduction on the planetary gear set.
Yu, Scott, Kaatz, Stephen
Technical Paper
Lessons Learned Through Working With General Motors2005-01-255105/16/2005
In many companies and corporations, a number of very good ideas never reach fruition, even after a substantial investment in time and money. Can corporations afford to squander such assets…or is it a result many other forces and variables that inadvertently conspire to failure? The Vibration Advisor Expert System is one of these great ideas with a significant amount of time and money invested and a proven functionality that didn't make it. This paper will describe the project and offer for discussion and thought, some of the reasons for implementation failure. It was the right tool at the right time - but it did not benefit the Corporation.
Pavlovcic, Frank W.
Technical Paper
The Design of an Inline GCI Chain CVT For Large Vehicles2004-40-005408/23/2004
The objective of this paper is to indicate the design principals of a Continuously Variable Transmission that is physically about the size of a conventional manual transmission for the same power and torque with an equal or better efficiency and durability. The CVT will be designed for use in either a hybrid electric drive or a conventional vehicle with the addition of a torque converter and reverse gear. The design objectives are as follows: 1. About the same size as a 5 or 6 speed manual transmission for North-South engine orientation and rear wheel drive. 2. About the same weight as the 5 or 6 speed manual transmission 3. Cost about the same or less 4. Much smaller than a comparable performance rated automatic transmission 5. Fewer parts than manual transmissions and less than 1/30th of the part count of an automatic. 6. Ratio span greater than equivalent manual or automatic transmissions. 7. Adaptable up to Class 8 trucks to replace 18 speed manual transmissions with 2000NM and
Brown, A. William, Rooij, Jacques Van, Frank, Andrew A.
Technical Paper
Dana Torque Vectoring Differential Dynamic Trak™2004-01-205305/04/2004
This paper presents a novel torque-vectoring (biasing) differential system Dynamic Trak™ that can be applied to both the inter-axle and the inter-wheel differential systems. The Dynamic Trak™ has three multi-plate clutches. The center clutch located inside the differential case provides a limited-slip or complete lock-up capability. The two outboard clutches positioned at either sides of the differential case selectively adjust the torque flow to the left or right shafts/wheels. An electronic control unit and a hydraulic circuit unit control the three clutches, realizing the active management of the torque to the two output shafts/wheels. The Dynamic Trak™ can provide maximum of 100% torque add or subtraction to the wheels, while maintaining the open differential feature. A virtual model representing a passenger car equipped with the Dynamic Trak™ has been developed. The simulation results show the handling and stability enhancements by the Dynamic Trak™.
Park, John, Kroppe, William J.
Technical Paper
P/M Applications for Heavy Duty Transfer Case2004-01-048703/08/2004
The 44-84 transfer case from BorgWarner is a new generation AWD/Part time 2-speed transfer case with a 2.64 low range. This transfer case was developed for the General Motors H2 and contains almost 31 pounds of powder metal components. The powder metal components range from single level gears, to two planetary carriers one of which is a two piece sinter brazed assembly and the other a highly designed 3 piece center differential which in open mode distributes torque in a 40/60-ratio front to rear. The center differential carrier body contains three sections and two different materials. In addition to the carrier body, the differential contains 8 pinion gears, which are P/M, and two sun gears, one of which is P/M.
Legault, Marc, Collins, Jim
Technical Paper
Fundamentals of Automotive All-Wheel Drive SystemsC030511/24/2003
This seminar provides an introduction to the fundamental concepts and evolution of passenger car and light truck 4x4/all-wheel drive (AWD) systems including the nomenclature utilized to describe these systems. Basic power transfer unit and transfer case design parameters, component application to system function, the future of AWD systems, and emerging technologies that may enable future systems are covered. This course is an excellent follow-up to the 98024-A Familiarization of Drivetrain Components seminar (which is designed for those who have limited experience with the total drivetrain). By attending this seminar, you will be able to: Identify front wheel drive and rear wheel drive vehicle architectures Identify part time, full time, and on demand all-wheel drive systems Explain the benefits of all-wheel drive over two-wheel drive Quantify all wheel drive traction and mobility benefits Describe auxiliary axle disconnect systems Explain basic vehicle dynamics performance and the
Instructor Led
Development of a 4WD System for SUVs2002-01-104203/04/2002
Surveys of sports utility vehicle (SUV) use in the United States, where they are extremely popular, show that they are mostly driven on streets in urban areas. However, most SUVs are based on a truck chassis, and off-road performance is regarded as more important than on-road handling and usability. Therefore, this system was created using an FF (front engine, front drive) passenger car chassis with functions integrated in the rear final drive unit, clutch units installed on the axle shaft for the left and right rear wheels, electronic torque control, torque limit control, and so on. The result combines the rough road performance required for an SUV with the handling of a passenger car. Further, this performance is achieved in a system weighing only 97 kg, making it the lightest in its class.
Tokushima, Shyouji, Nakano, Kazuhiro, Kuroda, Kouji, Konishi, Yoshikazu, Kobayashi, Kazunori
Technical Paper
Gear Shift Quality Improvement In Manual Transmissions Using Dynamic Modelling2000-05-012606/12/2000
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
Christopher Kent, David Kelly
Technical Paper
The Clonk Phenomenon - a Load Change Reaction to be Balanced in Terms of Comfort and Engine Response2000-05-032706/12/2000
The customers demand of a good vehicle agility consists of a quick reaction of the vehicle with the actuation of the throttle pedal on one hand and a high comfort level of vibration and noise within the vehicle on the other hand, which means the reduction of disturbing side effects. In order to achieve a satisfactory compromise it is necessary to gain a deeper understanding of the complex, high dynamic vibrations system “vehicle / drive train”. For several years the ika has been carrying out such detailed vehicle investigations and test bench measurements in addition to comprehensive CAE analysis for various research projects in partnership with different vehicle manufacturers.
J.-W.Biermann, Priv.-Doz. Dr.-Ing., Reitz, Dipl.-Ing. A., Schumacher, Dipl.-Ing. T.
Technical Paper
Chrysler 45RFE a New Generation Light Truck Automatic Transmission1999-01-126003/01/1999
The 45RFE is a new generation electronically controlled rear wheel drive automatic transmission. It employs real-time feedback, closed-loop modulation of shift functions to achieve outstanding shift quality and to meet demanding durability goals. It uses no shift valves; all friction element applications are effected with high-flow electro-hydraulic solenoid valves. A unique gear train arrangement of three planetary carriers allows all sun gears and annulus gears to have the same number of teeth respectively and use a common pinion gear in all carriers, resulting in significant manufacturing simplification. The three-planetary system is designed for four forward ratios of 3.00, 1.67, 1.00 and 0.75 and one reverse gear ratio equal to the low gear ratio. A fifth ratio of 1.50 is used only in certain kick-down shift sequences for highway passing. A sixth forward ratio, an additional overdrive ratio of 0.67, is available in the hardware. A unique valve body arrangement allows for two
Martin, Berthold, Redinger, Charles J., Dourra, Hussein
Technical Paper
Development of MMC Rally Car98306611/16/1998
Iwata, Hideyuki
Technical Paper
Development of a Shift By Wire Synchronized 5-Speed Manual Transmission98083102/23/1998
This paper describes the modification of a rear wheel drive manual transmission for the purpose of shifting using electromechanical actuators under microprocessor control. This Shift By Wire (SBW) technology has applications in automated manual transmission systems and shift assist systems. The system is optimized for shift comfort and shift speed. A test vehicle was outfitted with the system and evaluated. The development concerns for this type of program are discussed and prototype results of the undertaken program are presented.
Bansbach, Eric A.
Technical Paper
An Assessment of the Tire Noise Generation and Sound Propagation Characteristics of an ISO 10844 Road Surface97199005/20/1997
A road surface complying with the new International Standards Organization (ISO) specification was installed at an Arizona test facility (DPG site) in the winter of 1995/96. As part of the acoustic qualification of this site, comparative tests were conducted between this new surface, a Society of Automotive Engineers (SAE) sealed asphalt surface and an existing ISO surface in Michigan (MPG site). Initial testing with one vehicle and tire combination indicated that the new ISO surface produced ISO 362-1994 passby and coastby levels about 2 dB lower than sealed asphalt. Relative to the Michigan surface, the levels for the new Arizona ISO surface were 3 to 3½ dB lower. These differences were much greater than expected based on previously published studies of these two test surface types. Since the new surface was constructed to the ISO specification and meet the physical requirements for sound absorption coefficient, porosity, and surface texture, further investigation was conducted to
Donavan, Paul R.
Technical Paper
ECOTRONIC - The Continuously Variable ZF Transmission (CVT)97068502/24/1997
The paper describes the activities of the ZF company in the field of continuously variable transmissions, especially for passenger cars in the past, the present and the near future. As an independent supplier of transmissions for the car manufacturers ZF has to be prepared for the questions and demands of the car industry in the near future. The near future is the time for CVT's and the ZF engineers developed a strategy and a program of continuously variable transmissions for every driveline system. This program and strategy is also described in this paper.
Boos, Manfred, Mozer, Herbert
Technical Paper
Ford Explorer Control Trac 4x4 System95264511/01/1995
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.
Technical Paper
A Building Block Approach for Understanding Four Wheel Drive Systems: Past-Present-Future95264311/01/1995
This paper describes a building block approach for understanding the past, present and future four wheel drive systems. The emphasis will be on light trucks and sport utility vehicles. It will describe the advantages of four wheel drive and how it improves performance and safety. The building block approach is a tool for categorizing the basic systems in the market. Systems are separated into main component areas and are rated for the effect they have on the overall performance and safety. This paper can be used as a means for understanding a very complex 4x4 market.
Williams, Randolph C., Socin, Richard J., Varma, Sanjeev K.
Technical Paper
Market Trends in Manual Transmissions for Class 1-8 Vehicles92246811/01/1992
Sammut, Vincent P.
Technical Paper
Stages in the Development of Four-Wheel Drive Systems in Audi Passenger Cars91002001/01/1991
In terms of vehicle dynamics, four-wheel drive exhibits great capabilities as a power transmission system for high-performance passenger cars. There are now numerous different concepts for four-wheel drive configurations. To provide an overview of the different systems and their characteristics, this report first defines the design requirements for four-wheel drive systems. It then compares the alternative concepts in schematic form. Finally, the results of simulations and measurements are given to describe the characteristics of the quattro system developed by Audi in the various stages of its development.
Hessing, Bernd, Muller, Ernst, Stockmar, Jurgen
Technical Paper
The Kubota's New “Bi-Speed Turn” Mechanism90163009/01/1990
Generally, most of the agricultual tractors are equipped with a 4-Wheel-Drive (4WD) feature to get maximum traction. Indeed,the 4WD feature is maximum traction, but it also spoils the turning ability, especially it becomes very difficult to make tight turns. This means that the performance of work is spoiled in some situations as follows: (1) In a case when the tractor has to till the soil next to the previously tilled lane. (2) In a case when the tractor has to mow around the bases of trees or some other obstacles. (3) In a case when the tractor with a front loader has to change directions in a narrow space. Because of these problems, we researched and developed the “BI-SPEED TURN” feature to improve on these disadvantages.This feature can be used whenever the steering angle of the front wheel exceeds approximately 25 degrees, the front wheels automatically start turning nearly twice as fast. The result is the tractor can make tight turns smoothly.
Ikegami, Seiichi, Matsushita, Yasuhisa, Osuga, Masashi
Technical Paper
Tire-Roadway Friction Coefficients on Concrete and Asphalt Surfaces Applicable for Accident Reconstruction90010302/01/1990
Within the accident reconstruction community, skidmarks and yaw marks are utilized in the speed analysis portion of an investigation to determine vehicle speeds during an accident sequence. Many times in an accident involving tire marks, a skid test is performed at the scene with a law enforcement vehicle utilizing performance type tires to determine the coefficient of friction at the tire-roadway interface. The primary purpose of this paper is to quantitatively assess differences which may exist between performance type tires often utilized on law enforcement vehicles and typical production type passenger car tires relative to tire-roadway friction. Historically, the main source for friction coefficients at the tire-roadway interface within the accident reconstruction community has been from research conducted by Northwestern University. This published research was conducted in excess of twenty years ago, and, furthermore, is believed to have been largely conducted in the northern
Wallingford, Jerry G., Greenlees, Bill, Christoffersen, Steve
Technical Paper
GM All Wheel Drive Van89253911/01/1989
A new All Wheel Drive Astro/Safari Van has been developed to offer enhanced “on-road” performance in inclement weather. Its content is a blend of proven components from existing products and a new transfer case featuring a viscous clutch. The result is a vehicle with the traction and handling potential of four wheel drive plus the driving ease and riding comfort of its two wheel drive counterpart.
Hunter, Douglas W.
Technical Paper
A New Investigation Tool for the Dynamics of 4WD and 4WS Cars89009104/01/1989
VALEO's Road Simulation Test Bench has a number of features which make it a unique tool for the investigation of vehicle dynamic behavior, more particularly in relation with 4WD and 4WS concepts. Both these concepts rely on the road contact properties of tyres for improving vehicle handling characteristics. The Road Simulation Test Rig is a unique means of measuring wheel contact forces on the ground, which is not otherwise possible on the road; it is based on the combination of: four large diameter rollers, one for each vehicle wheel, which are each fitted with load sensors for the measurement of longitudinal, lateral and vertical forces a unique restraint mechanism for preventing forward or rearward movements of the vehicle, leaving entire freedom, within limits, for all other movements: lateral and vertical translations, pitch, roll and yaw around the vehicle center of gravity. On this rig, the roller width enables expressway lane change maneuvers to be carried out, and large radius
Filderman, R., Focqueur, H.
Technical Paper
Toyota EC-HYMATIC – A New Full Time 4WD System for Automatic Transmission89052602/01/1989
Toyota has developed a new full time 4WD system, called “EC-HYMATIC” or Electronically Controlled - HYdraulic Multi-plate clutch Active Traction Intelligent Control. This system permits an automatic torque transfer, depending on driving conditions, for front and rear wheels under control of the speed difference between the two. The system developed consists of a center differential, a speed difference control clutch system employing multi-plate clutch, and a gear set for rear axle drive. The speed difference control clutch system is controlled by a unique electro-hydraulic system using a microcomputer. An extensive use of computer simulations and vehicle test and evaluation has successfully developed an appropriate control strategy for the clutch system. The new 4WD system, EC-HYMATIC, considerably improves handling characteristics, traction performance and stability of a 4WD vehicle.
Taniguchi, Takao, Yokoyama, Fumitomo, Nakamura, Shinya, Ishikawa, Masakazu, Akashi, Teruo
Technical Paper
Linking Evaluation Of Subjective Handling Tests On The Road With Objectively Measured Data By Using Fuzzy-Set-Theory88500609/01/1988
High speed tires were measured on the road and in the lab, both on a rear wheel drive and a front wheel drive vehicle. The tests described refer to standard methods used in the tire industry. They include various tire patterns as well as direction-oriented patterns. Depending upon vehicle type and driven axle, the subjective test result in varying sequences in the main groups of tested parameters - slalom, curve behaviour, handling characteristics and steering response. Static, quasi-static and dynamic measurements on tires were performed in the Semperit lab. The data obtained in the lab did not result in distinct sequences. In case we have to decide which tire is best suited for the intended purpose, the basis for decisions in neither precise nor clear, and conventional engineering mathematics will not suffice. Therefore, “Fuzziness” has to be introduced. The basis of the Fuzzy-Set-Theory is a maximum/minimum principle. The Fuzzy-Set-Theory is a mathematical structure capable of
Stumpf, H., Arendt, G., Lux, F.
Technical Paper
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