Browse Topic: Rear wheel drive

Items (100)

Integrated Multi-Physics Simulation for Full-Vehicle Low Frequency NVH Optimization in HEVs

2019-01-14556/5/2019

The recent automotive industry trend towards electrification has created new challenges for NVH engineers. These challenges stem from new powertrain architectures and their complex interactions, the governing control strategies which aim to optimize energy management, and new unmasked sources of excitation. Additionally, vehicle manufacturers are attempting to reduce hardware testing in order to rapidly satisfy increasing production demand and to minimize its costs. Hence, to meet the above-mentioned challenges up front in the development process of Hybrid Electrical Vehicles (HEVs) while balancing competing design objectives of drivability, durability and NVH, a simulation-led design and optimization is required. NVH problems are often the result of mechanisms that originate through complex interactions between different physical domains (flow, electromagnetic, structural/mechanical, control logic, etc.) and the assembly of individual components into a complete system. Therefore, accurate system-level integrated models are becoming a requirement to solve modern NVH problems. Combining the optimal balance between simulation and experimental data, this article describes a joint effort between Ford and Gamma Technologies to develop a general methodology to perform full-vehicle low frequency NVH analysis. Using GT-SUITE software, a non-linear multi-physics simulation model of a rear wheel drive HEV was created. The model was exercised to accurately evaluate the effects of powertrain control strategy and component selection on low-frequency NVH performance during a tip-in regeneration, downshifting and in-gear acceleration maneuvers while minimizing the computational cost.

Gomez, Llorenc Foraste, Zeman, Jonathan, Liu, Jack

Development of Innovative Dynamic Torque Vectoring AWD System

2019-01-03324/2/2019

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

2020 Ford Explorer: Knockout styling surrounds all-new engineering

19AUTP08_201/1/2019

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. “When you're all new, you get to go after all that. You get a chance to wipe the slate clean.”

Seredynski, Paul

Cadillac pulls the wraps off two new V-Series sedans

19AUTP08_191/1/2019

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

Porsche reveals eighth-generation of fabled 911

19AUTP01_151/1/2019

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

All-Wheel Drive Systems Classification

J1952_201804 (Current)

4/18/2018

In this SAE Recommended Practice, attention will be given to passenger cars and light trucks (through Class III).

Drivetrain Standards Committee

Simulation Based Control Strategy Design of All Wheel Drive Electric Vehicle Regenerative Braking System

2018-01-04114/3/2018

Bao, Ran, Griggs, Philip, Baxter, James

WHAT WE'RE DRIVING2018 Volvo XC60 T8 Inscription

17AUTP11_1411/1/2017

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.

Torsional Vibration Analysis of Six Speed MT Transmission and Driveline from Road to Lab

2017-01-18456/5/2017

When a manual transmission (MT) powertrain is subjected to high speeds and high torques, the vehicle driveshaft, and other components experience an increase in stored potential energy. When the engine and driveshaft are decoupled during an up or down shift, the potential energy is released causing clunk during the shift event. The customer desires a smooth shift thus reduction of clunk will improve experience and satisfaction. In this study, a six-speed MT, rear-wheel-drive (RWD) passenger vehicle was used to experimentally capture acoustic and vibration data during the clunk event. To replicate the in-situ results, additional data was collected and analyzed for powertrain component roll and pitch. A lumped parameter model of key powertrain components was created to replicate the clunk event and correlate with test data. The lumped parameter model was used to modify clutch tip-out parameters, which resulted in reduced prop shaft oscillations. By reducing the prop shaft oscillations the clunk phenomena can be reduced and customer satisfaction increased.

Furlich, Jon, Blough, Jason, Robinette, Darrell

A Study on the NVH Problems Caused by the Additional Excitation Force of Propeller Shaft

2017-01-17686/5/2017

The NVH performance is one of the most important concerns in vehicle development. For all-wheel drive (AWD) vehicles and rear-wheel (RWD) drive vehicles, prop shaft is a major transmission component which may cause various NVH problems. This paper focuses on the vehicle NVH problems caused by the second order excitation force of prop shaft. In order to control the NVH performance of the prop shaft efficiently and fundamentally, this work first studied the rotation kinematical characteristics of prop shaft. Then a rigid-elastic coupling model of vehicle driveline was built with the theory of multi-body dynamics. With this model, the sensitive factors that may affect the second order excitation force were investigated. This paper also describes a case study to verify the conclusions which are revealed from the theoretical calculation and the simulation. In this case, a vehicle vibration problem caused by the second order excitation force of prop shaft was successfully solved by following the indicative conclusions mentioned above. The main significance of this study is to establish an effective approach for analyzing and controlling the NVH issues related to vehicle driveline system. The indicative conclusions of this work could be referred by NVH engineers in the early phase of vehicle development.

Xu, Yong

Model Based Approach by Combination of Test and Simulation Methodologies for NVH Investigation and Improvement of a Rear Wheel Drive Vehicle

2017-01-17746/5/2017

The increasing pressure on fuel economy has brought car manufacturers to implement solutions that improve vehicle efficiency, such as downsized engines, cylinder deactivation and advanced torque lock-up strategies. However, these solutions have a major drawback in terms of noise and vibration comfort. Downsized engines and lock-up strategies lead to the use of the engine at lower RPMs, and the reduced number of cylinders generates higher torque irregularities. Since the torque generated by the engine is transferred through flexible elements (clutch, torsional damper, gearbox, transmission, tire), these also impact the energy that is transferred to the vehicle body and perceived by the driver. This phenomenon leads to low frequency behavior, for instance booming noise and vibration. This paper presents a combined test and CAE modelling approach (1D/3D) to reverse engineer a vehicle equipped with a CPVA (centrifugal pendulum vibration absorber). The objectives were to fully understand and predict vehicle behavior with respect to the drivetrain torsional oscillations and low frequency booming noise and vibration. For this purpose, the procedure was divided in two phases: testing and modelling. The testing phase was used to get insight into the vehicle behavior, noise sources and noise transfer paths, using operational measurements. Moreover, dedicated component tests were carried out to obtain parameters to be used in the modelling phase, with the CPVA being the most complex and important component. The modelling phase used the test results as input to build a full vehicle model and to validate the booming noise results. The final model was fit for sensitivity studies and was also used to evaluate the performance of the CPVA, which is dedicated to the reduction of lock-up booming noise. Such an approach is a first step which can accelerate the SDPD (system driven product development) into a consolidated MBSE (model based system engineering) framework.

Marques dos Santos, Fabio Luis, Enault, Tristan, Deleener, Jan, Van Houcke, Tom

General Motors’ New Reduced Scale Wind Tunnel Center

2017-01-15343/28/2017

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

Torsional Vibration Analysis of the Driveline on Light Weight Rear Wheel Drive Vehicle

2017-26-02191/10/2017

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 operational torsional vibration analysis was carried out on the driveline to identify the deflection shape and root cause for severe vibration. A dynamic torsional absorber used in the driveline has reduced torsional vibration to a great extent. The vibration levels are reduced by ∼50%. Also, the outcome of subjective jury conducted is that the noise levels are at completely acceptable level. The design and balancing specifications of torsional damper along the drive shaft is further enhanced to reduce the vibration levels and to sustain the durability criteria considering the real world usage pattern of the vehicle. Alternate methods like enhancing the suspension isolation, body stiffening and translational tuned mass damper are also investigated and their effect is analyzed.

Moorthy, S Nataraja, Rao, Manchi, Raghavendran, Prasath

Associated Controls Systems Development Application via Parallel Post Transmission Rear Wheel Drive for Plug in Hybrid Electric Vehicle

2016-01-215410/17/2016

The EcoCAR3 team of California State University, Los Angeles designed a Parallel Post Transmission Plug-in Hybrid Electric Vehicle (PPT PHEV) that will maintain consumer acceptability in the areas of performance, utility and safety with the end-goal of reducing Well-to-Wheel Green House Gas (WTW GHG) emissions and Well-to-Wheel Petroleum Energy Use (WTW PEU). The team utilizes the 2016 Chevrolet Camaro platform with modifications such as 2.4L Ecotec engine, a 134 HP electric motor and a 12.6 KW/h battery pack. The vehicle is estimated to have a fuel economy of 58.7 miles per gallon gasoline equivalent (mpgge). This paper presents the vehicle’s two main operating modes, Electric Vehicle (EV) and Hybrid-Electric Vehicle (HEV) while performing Environmental Protection Agency (EPA) certified drive cycles: 505, HWFET, US06 City and US06 HWY. Also presented, is the optimized propulsion control strategy which lowers WTW GHG and WTW PEU achieved while extending energy storage system life, increasing the mpgge to 59.6 under the new modified control strategy defined as “I.W.U.” (Internal Combustion Engine and Warm Up) mode. The implementation of the new mode allows the full deployment of propulsion, achieving competition and team design targets. In addition, results from running EPA drive cycles with this optimized control strategy, including fault diagnostic section, are presented in this paper. All modeling and simulation data was obtained using Autonomie software from Argonne National Laboratories. This endeavor was made possible with the support from the United States Department of Energy, General Motors, Argonne National Laboratory, Mathworks and other sponsors.

Alvarez, Ary Armando, Muñoz, Eufemio

High Fidelity Quasi Steady State Aerodynamic Model Development and Effects on Race Vehicle Performance Predictions

2016-01-15894/5/2016

Presented in this paper is a procedure to develop a high fidelity quasi steady state aerodynamic model for use in race car vehicle dynamic simulations and its application in a race vehicle multi-body full lap simulation. Developed to fit quasi steady state (QSS) wind tunnel data, the aerodynamic model is regressed against three independent variables: front ground clearance, rear ride height, and yaw angle. An initial dual range model is presented and then further refined to reduce the model complexity while maintaining a high level of predictive accuracy. The model complexity reduction decreases the required amount of wind tunnel data thereby reducing wind tunnel testing time and cost. The quasi steady state aerodynamic model for the pitch moment degree of freedom is systematically developed in this paper. This procedure is extended to the other five aerodynamic degrees of freedom to develop a complete, high fidelity, six degree of freedom quasi steady state aerodynamic model. This high fidelity model reduces the QSS aerodynamic fit error compared to conventional aerodynamic model development. Both the newly developed high fidelity aerodynamic model and a conventionally derived aerodynamic model are implemented in a NASCAR Truck multi-body, full lap QSS simulation to determine the effects of the high fidelity QSS aerodynamic model on the simulation results. Performance metrics are calculated from simulation results and compared to assess the effects of the aerodynamic models on the performance predictions. The increased accuracy of the high fidelity aerodynamic model is found to have discernable effects on the vehicle performance predictions resulting from the QSS simulation.

Mohrfeld-Halterman, Jackie A., Uddin, Mesbah

The GM RWD PHEV Propulsion System for the Cadillac CT6 Luxury Sedan

2016-01-11594/5/2016

This paper describes the capabilities of a new two-motor plug-in hybrid-electric propulsion system developed for rear wheel drive. The PHEV system comprises a 2.0L turbocharged 4-cylinder direct-injected gasoline engine with the new hybrid transmission [1], a new traction power inverter module, a liquid-cooled lithium-ion battery pack, and on-board battery charger and 12V power converter module. The capability and features of the system components are described, and component performance and vehicle data are reported. The resulting propulsion system provides an excellent combination of electric-only driving, acceleration, and fuel economy.

Grewe, Timothy, Liu, Jinming, Anwar, Mohammad, Holmes, Alan, Balsley, Richard

Development of an End-of-Line Driveline System Balance Tester

2015-01-21876/15/2015

This paper describes the development of a semi-automated end-of-line driveline system balance tester for an automotive assembly plant. The overall objective was to provide final quality assurance for acceptable driveline noise and vibration refinement in a rear wheel drive vehicle. The problem to be solved was how to measure the driveline system unbalance within assembly plant constraints including cycle time, operator capability, and integration with a pre-existing vehicle roll test machine. Several challenging aspects of the tester design and development are presented and solutions to these challenges are addressed. Major design aspects addressed included non-contacting vibration sensing, data acquisition/processing system and vehicle position feedback. Development challenges addressed included interaction of engine and driveline vibration orders, flexible driveline coupling effects, tachometer positional reference error, and vehicle-to-vehicle variation of influence coefficients.

Gehringer, Mark A., Thompson, Keith

Experimental Investigation of Effect of Driveline Torsional Fluctuations on Overall NVH Performance of the Vehicle

2015-01-21926/15/2015

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 levels of torsional vibration input to the vehicle. The threshold level of torsional fluctuation for the given vehicle structure is obtained by taking into account the target values of tactile vibration and subjective perception. The results are very useful in deciding the acceptable level of change in engine power without carrying any structural change. Also, for a given power, the set of structural changes necessary in the body and suspension linkages to meet the NVH criteria can be studied. The procedure is also extended to an all-wheel drive vehicle with the help of a two wheel drive chassis dynamometer. Obtaining subjective perception of the vehicle NVH even before making the vehicle of target configuration is an inherent advantage of the proposed technique. A good correlation is achieved with the objective results and subjective perception.

Rao, Manchi Venkateswara, Frank, Jos, Raghavendran, Prasath

Experimental Investigation of Power Hop in Passenger Cars

2015-01-21856/15/2015

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 amplitude and frequency in dependence of the car. In case of power hop, the sensor information of the engine displacement as well as the drive shaft torque and the rotational speed of the driven wheels show the same frequencies. It is illustrated that the absolute value of the engine torque during acceleration has smaller effect on the power hop frequency but greater impact on the intensity and duration of the oscillations. As a result, it is concluded that a suitable control of the engine torque during acceleration might reduce the phenomenon of power hop.

Eicke, Simon, Zemke, Steffen, Trabelsi, Ahmed, Dagen, Matthias, Ortmaier, Tobias

Dual Degree of Freedom Vibration Damper (DDVD) for Driveline Noise and Vibration Issue Resolution

2015-01-21776/15/2015

Powertrain and driveline systems interaction in rear wheel drive vehicle development has recently gained attention for the improvement of interior noise and vibration in emerging markets. The driveline is a significant path for engine-generated noise and vibration to reach the interior occupant interfaces, where it affects refinement perception. The interaction of powertrain excitation orders and driveline resonant responders covers a wide range of frequency and vehicle operating conditions. This interaction poses significant challenges during vehicle development. With recent increased demand for higher specific power from diesel engines, driveline refinement has become even more challenging, especially for rear wheel drive vehicles. Two driveline related refinement issues were observed during evaluation of a RWD vehicle. Root cause analysis determined that the first issue (lower rpm boom noise and vibration) was due to engine torsional excitation of the driveline. The second issue (higher overall noise at higher rpm) was due to a propeller shaft bending resonance. Separate solutions using known technology were available for the two issues; a Torsional Vibration Damper (TVD) for the torsional boom and an Internal Tuned Damper (ITD) for propeller shaft bending resonance. The challenge was to find a new single solution which could mitigate both issues without affecting current driveline architecture. A Dual DoF Vibration Damper (DDVD) was developed to solve the above mentioned driveline noise and vibration issues. The DDVD is designed and tuned to work as torsional vibration damper in the rotational direction and as linear vibration damper in the radial direction. The paper describes the design and tuning of the DDVD to reduce the two critical driveline induced noise and vibration issues. The problem description, root cause steps, and alternate solutions prior to DDVD development are also discussed.

Vikram, MR, Gehringer, Mark, Patil, Ramesh

Eco-Driving System for Energy Efficient Driving of an Electric Bus

2015-01-01584/14/2015

This paper presents the design of an Eco-Driving Assistant System (EDAS) in which the main goal is to minimize the energy use of battery electric vehicles, in particular, vehicles utilized for public transportation. The system optimizes the speed profile of a real route schedule while satisfying the constraints imposed on speed and time. It includes a driver feedback and a driver scoring GUI which allows the driver improving his/her driving skills and comparing him/herself to a “theoretical perfect driver”. The system also includes a backward simulator that generates information related to the vehicle operation under the particular route to be optimized. The output information from the simulator is used as an input to the optimization algorithm. The simulator was validated using real data from a battery electric vehicle. The EDAS system was tested for three different driving profiles and energy consumption reductions of up to 30.33% were achieved.

Rios-Torres, Jackeline, Sauras-Perez, Pablo, Alfaro, Ruben, Taiber, Joachim, Pisu, Pierluigi

Advanced Technology for Dry Multi-Plate Clutch in FWD HEV Transmission (JATCO CVT8 HYBRID)

2015-01-10944/14/2015

There has been a growing need in recent years to further improve vehicle fuel efficiency and reduce CO2 emissions. JATCO began mass production of a transmission for rear-wheel-drive (RWD) hybrid vehicle with Nissan in 2010, which was followed by the development of a front-wheel-drive (FWD) hybrid system (JATCO CVT8 HYBRID) for use on a midsize SUV in the U.S. market. While various types of hybrid systems have been proposed, the FWD system adopts a one-motor two-clutch parallel hybrid topology which is also used on the RWD hybrid. This high-efficiency system incorporates a clutch for decoupling the transmission of power between the engine and the motor. The hybrid system was substantially downsized from that used on the RWD vehicle in order to mount it on the FWD vehicle. This paper describes various seal technologies developed for housing the dry multi-plate clutch inside the motor, which was a key packaging technology for achieving the FWD hybrid system.

Aoyagi, Tsuyoshi, Ishii, Shigeru, Uehara, Hiroki

Effect of Direct Yaw Moment Control Based on Steering Angle Velocity and Camber Angle Control

2014-01-23869/30/2014

It has been reported that steering systems with derivative terms have a heightened lateral acceleration and yaw rate response in the normal driving range. However, in ranges where the lateral acceleration is high, the cornering force of the front wheels decreases and hence becomes less effective. Therefore, we applied traction control for the inner and outer wheels based on the steering angle velocity to improve the steering effectiveness at high lateral accelerations. An experiment using a driving simulator showed that the vehicle's yaw rate response improved for a double lane change to avoid a hazard; this improves hazard avoidance performance. Regarding improved vehicle control in the cornering margins, traction control for the inner and outer wheels is being developed further, and much research and development has been reported. However, in the total skid margin, where few margin remains in the forward and reverse drive forces on the tires, spinout is unavoidable. Therefore, we applied tire camber angle control to improve vehicle maneuverability in the total skid margin. An experiment using a driving simulator has confirmed that the vehicle's lateral acceleration at the turning limit can be improved by controlling the camber angle. Because of this, camber angle control promises to be more effective than traction control for the inner and outer wheels. By applying this type of steering control, it is possible to increase maneuverability and stability in the cornering margins.

Yoshino, Takahiko, Nozaki, Hiromichi

Electric Drive System for SPORT HYBRID SH-AWD

2014-01-18214/1/2014

We have developed the new SPORT HYBRID SH-AWD system, a hybrid system that provides best in class fuel economy and drivability to exceed customer expectations. The powertrain has a V6 engine and comes with three drive types modes: front wheel drive powered by a 7-speed dual clutch transmission with one built-in motor, rear wheel drive powered by a twin motor unit with two built-in motors, and all-wheel drive powered by a combination of the two. The system can automatically select the most efficient drive method for the driver's needs and the road conditions. The two motors built into the twin motor unit are individually controlled and torque vectoring is used to create a torque difference between the left and right tires, improving the turning performance. The electric drive system was developed with consideration for layout feasibility and quietness. The two motors built into the twin motor unit and the inverter that drives the motors have been newly developed. By installing this system in the 2015 model year RLX, we achieved engine performance equivalent to a car with a V8 engine at 0-60 mph in 5.4sec and fuel economy equivalent to a car with an L4 engine at 30 mpg.

Ono, Koichi

Implementation of an Electronic Differential Using Torque Vectoring

2014-01-17764/1/2014

This paper involves the study of implementation of an active electronic differential using torque vectoring in an electric rear wheel drive vehicle. The proposed system works in a closed loop taking feedback in real time from sensors which provides inputs for steering angle, throttle position, angular velocity of wheels, yaw rate, yaw acceleration, longitudinal acceleration and lateral acceleration. The objective of this system is to i) increase the stability and the vehicle response to the driver while turning, and ii) use the traction available on the driven wheels more efficiently. The system involves applying a torque difference between the rear driven tires to create a moment about the centre of mass that causes yaw acceleration and aids in turning the car by increasing yaw rate. The effect of drag forces and the lateral forces on the tires have been included. An optimized desired moment is calculated which is applied via torque difference while turning. A Permanent Magnet DC (PMDC) motor model and a model for the motor controller in torque mode have been developed based on experimental response analysis on a jig setup. A detailed race car model for longitudinal vehicle dynamics is derived from forces acting on the car including the effect of losses due to drag forces, rolling resistance, transmission inefficiency and inertial losses. To validate the proposed system, various throttle profiles and steering inputs are simulated on the vehicle model during a turn. The results are compared to the case when vehicle is turning without using torque differential.

Sakhalkar, Siddhesh, Dhillon, Parveen, Kumar, Pranay, Bakshi, Soovadeep, Arora, Puneet Singh

All-Wheel Drive Systems Classification

J1952_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

Simulation of Restart Gradability of a Manual Transmission Vehicle Using AVL-CRUISE

2013-01-251610/14/2013

1 With increasing fuel price, the power train size is on a downward trend. For Fuel Economy maximization, the engine capacity and reduction ratios are getting reduced. So gradability of a vehicle is becoming a trade off factor for the power train size finalization in a car. At the same time OEMs are working hard to maintain profitability by reducing development and operational cost and time. In this complexly competitive scenario in automobile manufacturing, simulation is gaining an upper hand over actual testing as simulation consumes lesser time and resource as compared to actual testing. This paper is aimed at developing a simulation technique for restart or stop and start gradability which is a very critical parameter for finalization of engine torque characteristics and power train configuration. The simulation is done on AVL-CRUISE software.

Gangopadhyay, Sarvanu

Optimization through NVH Analysis to Improve the Vehicle Acoustics and Quality of Transmission Shifter

2013-01-24459/24/2013

Gear shift quality and feel determines the performance of the transmission. It is dependent on the synchronizer, shift system, gear shifter etc in a transmission. In this study the impact of the transmission shifter on the gear shift feel is detailed. More focus is paid towards the feel in terms of NVH characteristics. The rear wheel drive transmission shifter can be bifurcated into direct and indirect shift type. Indirect shifter are of two types, the rod type shifter and the cable shifter. The rod type shifter is analyzed in detail. All the shifters are connected to the gear shift top lever which is the customer interface for gear shifting. The design of the top lever is critical in getting the optimal feel of shifting and the mounting of the shifter is critical to improve its NVH characteristics. Different design iteration of the top lever are studied to illustrate the impact of the weight and stiffness on the vibration. CORRELATION OF A SEMI REMOTE SHIFTER MOUNTING ON VEHICLE ACOUSTICS AND VIBRATION is also established. The shifter dynamics are simulated and its NVH characteristics were studied for 4 cylinder engine and 3 cylinder engine. The shifter strength is analyzed with CAE on hyper mesh. The mechanical links involved and the iterations done to improve the shift quality as well the vibration levels of the hand ball are described. The biasing and shifting force and the travel of the knob in each gear are optimized by verifying through GSQA. Various rear wheel drive transmission have been used as an example to illustrate the shifter dynamics and efficiency. In a three cylinder engine the optimization of the semi remote shifter for the vibration and noise is critical. The solution can be common with a 4-cylinder engine if the arrangement is similar. The extent of benefit would be less on the 4-cylinder than with the 3-cylinder engine as it is more balanced. This study deals primarily with the mounting scheme of the semi remote shifter and its impact on the vehicle NVH. As the 3-cylinder engine configuration has the maximum drive train vibration, it enables a better understanding of the impact of the semi remote shifter mounting scheme on the vehicle. The analysis would help in the selection of the optimum semi remote shifter configuration and material with design adaptation suited to the engine configuration providing better NVH result on the vehicle.

Singh, Jaideep, Balpande, Ajay, Chaudhary, Anshika, Kumar, Sanjeev

Using Vehicle Simulation to Investigate Controllability

2013-01-01804/8/2013

All functional safety standards have some definition of “risk” and the automotive standard ISO 26262 is no exception. Risk is related to the exposure, the severity of the outcome, and in the case of ISO 26262, the controllability in relation to a specific vehicle hazard or hazards associated with the behavior of the vehicle or part of the vehicle. Thus hazards are central to understanding the risk associated with systems. When considering traditional power train systems, based on internal combustion engines or centralized electric motors, hazards are most usually limited to unintended acceleration and deceleration. The situation is complicated somewhat with the introduction of electronically controlled differentials, which can induce limited amounts of induced yaw, as can ABS and ESC. In a similar manner, replacing the centralized driveline system with in-wheel electric motors brings with it a similar set of issues. In this paper we describe the work undertaken to qualitatively identify the hazards associated with in-wheel motors and to quantify the vehicle level effects that could be expected. With this being done to ensure that, when realized as an engineering object, the level of controllability and hence the residual risk to a vehicle fitted with in-wheel motors remains within tolerable bounds.

Ellims, Michael, Monkhouse, Helen Elizabeth, Harty, Damian, Gade, Teena

Active Kinematics Suspension for a High Performance Sports Car

2013-01-06844/8/2013

The challenge to design the rear suspension of a rear wheel drive sports car has always been one of optimizing the position of both wheels and therefore the contact patch of the tires in order to obtain the maximum possible limit acceleration. This project takes the active kinematics idea a step further, and for the first time, we present an active system which allows complete control of the wheel by controlling the toe and camber angles on the fly. This allows a more complete control of the contact patch condition which can then further optimize the overall dynamics of the vehicle. This system, called Active Kinematics Suspension (AKS), is realized by four electromechanical actuators (two per side) in a sophisticated multilink axle. This allows direct manipulation of the camber and toe angles of the rear wheels by changing the length of two of the links. A high level vehicle dynamics controller then drives this system based on achieving two measurable targets; 1 Improvement of the frequency response to steering input. This is appreciated by the driver as higher precision steering and better overall driveability. 2 Improvement of the traction performance by increasing the grip at the limit, and also increasing the stability below the limit. A high level of synergy between camber and toe control has been defined, optimizing lateral acceleration gain and delay (camber) and yaw rate gain and delay (toe) Virtual tests and evaluation have shown an outstanding performance advantage when compared against the baseline vehicle's original passive kinematics.

Ramirez Ruiz, Isabel

The Development of FR-Based 4WD Multi-Link Suspension

2013-01-12354/8/2013

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

Vehicle Integration Factors Affecting Brake Caliper Drag

2012-01-18309/17/2012

Disc brakes operate with very close proximity of the brake pads and the brake rotor, with as little as a tenth of a millimeter of movement of the pads required to bring them into full contact with the rotor to generate braking torque. It is usual for a disc brake to operate with some amount of residual drag in the fully released state, signifying constant contact between the pads and the rotor. With this contact, every miniscule movement of the rotor pushes against the brake pads and changes the forces between them. Sustained loads on the brake corner, and maneuvers such as cornering, can both produce rotor movement relative to the caliper, which can push it steadily against one or both of the brake pads. This can greatly increase the residual force in the caliper, and increase drag. This dependence of drag behavior on the movement of the brake rotor creates some vehicle-dependent behavior. Major factors affecting rotor movement include wheel bearing stiffness, wheel radius, vehicle mass and mass distribution, and brake corner geometry. The present work studies two vehicle-integration dependent mechanisms which can affect brake drag. The first involves rotor movement due to sustained tire/wheel loading conditions and brake corner geometry, and is examined through a case study involving two vehicles. The second involves rotor movement due to cornering loads. In both cases, rotor movement is related to brake drag by component dynamometer measurements of brake drag versus small axial movements of the rotor.

Antanaitis, David B.

Optimization of a Multiple-Speed Transmission for Downsizing the Motor of a Fully Electric Vehicle

2012-01-06304/16/2012

The research presented in this paper focuses on the effects of downsizing the electric motor drive of a fully electric vehicle through the adoption of a multiple-speed transmission system. The activity is based on the implementation of a simulation framework in Matlab / Simulink. The paper considers a rear wheel drive case study vehicle, with a baseline drivetrain configuration consisting of a single-speed transmission, which is compared with drivetrains adopting motors with identical peak power but higher base speeds and lower peak torques coupled with multiple-speed transmissions (double and three-speed), to analyze the benefits in terms of energy efficiency and performance. The gear ratios and gearshift maps for each multiple-speed case study are optimized through a procedure developed by the authors consisting of cost functions considering energy efficiency and performance evaluation. The cost functions are explained in the paper along with the models adopted for the research.

Di Nicola, Francesca, Sorniotti, Aldo, Holdstock, Thomas, Viotto, Fabio, Bertolotto, Stefano

Integrating In-Wheel Motors into Vehicles - Real-World Experiences

2012-01-10374/16/2012

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 existing vehicle portfolio in order to address more stringent fleet-average emissions legislation. Protean has retrofitted its Protean Drive™ in-wheel motors to a variety of different vehicles in both pure EV and hybrid configurations and has collated its findings over three years of track and road testing. This paper will distil the practical experience gained from these vehicle programs and illustrate some of the challenges and solutions associated with in-wheel motor integration. In doing so the paper deals with many of the key vehicle level topics, such as the CAN interface, vehicle control strategy, and brake integration.

Watts, Andy, Vallance, Andrew, Fraser, Al, Whitehead, Andrew, Hilton, Christopher, Monkhouse, Helen, Barrie-Smith, John, George, Sunoj, Ellims, Michael

The Technology and Economics of In-Wheel Motors

2010-01-230710/19/2010

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

Effect of Different Magnesium Powertrain Alloys on the High Pressure Die Casting Characteristics of an Automatic Transmission Case

2010-01-04094/12/2010

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 between the alloys with respect to surface and internal imperfections based on the runner design used in the trials. In addition, it was found that different gating techniques are needed when casting the MRI alloys.

Jekl, John, Berkmortel, Richard D., Armstrong, Paula

Optimization for Shared-Autonomy in Automotive Swarm Environment

2009-01-01664/20/2009

The need for greater capacity in automotive transportation (in the midst of constrained resources) and the convergence of key technologies from multiple domains may eventually produce the emergence of a “swarm” concept of operations. The swarm, a collection of vehicles traveling at high speeds and in close proximity, will require management techniques to ensure safe, efficient, and reliable vehicle interactions. We propose a shared-autonomy approach in which the strengths of both human drivers and machines are employed in concert for this management. A fuzzy logic-based control implementation is combined with a genetic algorithm to select the shared-autonomy architecture and sensor capabilities that optimize swarm operations.

Bai, Sue, Sengstacken, Aaron, DeLaurentis, Daniel

Vehicle Handling and Control Following Front Ball Joint Failure

2008-01-01714/14/2008

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 are examined. Finally, the results of a series of tests are discussed in which ball joint failures are caused to occur as the vehicle is being driven. The effect of these failures on vehicle handling and control is described and compared with the predictions from the design analysis. Finally, the physical evidence left on the vehicle and roadway by the failures is described.

Dunn, Ashley L., Tanner, C. Brian, Stansifer, Rickey L., Doyle, Sean A., Guenther, Dennis A.

Studying the Effects of Lapping Process on Hypoid Gears Surface Finish and Transmission Errors

2007-01-22295/15/2007

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 shown that lapping decreases transmission errors for both sides (drive and coast). Utilizing a Gleason single flank tester 600HTT it will be shown experimentally that transmission errors up to the third harmonics for both sides will be decreased. In addition, it can be seen that lapping decreases surface finish variation among gear sets.

Masseth, Jack, Kolivand, Mohsen, Blancke, Harry, Wright, Ned

Statistical Relationship between Corner Weight and Spindle Load

2007-01-13464/16/2007

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 lateral spindle load and corner weight with R-square greater than 0.5; however, poor statistical relationship between fore/after spindle load and corner weight is found.

Cao, Cheng, Medepalli, Sudhakar

Hybrid System Development for High-Performance All Wheel Drive Vehicle

2007-01-02964/16/2007

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

Friction Coefficient on Snowy and Icy Surfaces of Pneumatic Tires Fitted with or without Anti-Skid Devices

2006-01-05604/3/2006

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

Lightweight Construction Due to Thermoplastic Foams as Exemplified in an Instrument-Panel Support

2006-01-14044/3/2006

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

Evaluating The Rolling Contact Fatigue Properties Of Surface Densified PM Gears

2006-01-03954/3/2006

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 the shear stress profile, need to be considered as design criteria.

Lawcock, Roger

Getting validation

AUTOAPR06_124/1/2006

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

Lessons Learned Through Working With General Motors

2005-01-25515/16/2005

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.

Asymmetric Gear Noise Sidebands and Application to Planetary Gear Noise Reduction

2005-01-24625/16/2005

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

The Design of an Inline GCI Chain CVT For Large Vehicles

2004-40-00548/23/2004

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 500kw capacity. 8. Higher efficiency and quieter than a manual transmission. 9. Durability equal to or greater than a manual transmission. 10. Very low noise. 11. Complete flexibility in control using computer controllers for fully automatic to manual ratio control for cars and trucks. The paper will discuss the specific design philosophy of a 500 NM, 250 kw CVT for a SUV and truck application and it’s installation. The prototype is designed for volume production by minimizing the number of parts. The total number of parts for this completely automatic transmission will be about 12 including all bearings. We will focus on the In-line CVT design for the front engine rear wheel drive cars with the design of this paper, but for front wheel drive vehicles a single stage CVT design will generally be the preferred. A discussion of the low cost high accuracy and low power control system used in this transmission will be provided. The geometry used shows the simplicity and flexibility of the design to satisfy a wide range of applications. The components used for the design will be discussed. The following Figure 1, shows the proposed concept. This concept is expected to be installed in a Ford Explorer for demonstration at the CVT-hybrid2004 Congress. It replaces a 5 or 6 speed manual transmission.

Brown, A. William, Rooij, Jacques Van, Frank, Andrew A.

Dana Torque Vectoring Differential Dynamic Trak™

2004-01-20535/4/2004

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.

P/M Applications for Heavy Duty Transfer Case

2004-01-04873/8/2004

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

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