Browse Topic: Front wheel drive

Items (158)

NVH Refinement of Structure borne tonal noise in electric vehicle

2024-26-019801/16/2024

Globally all OEMs are moving towards electric vehicle to reduce emission and manage fuel cost. Customers expect highest level of refinement and sophistication in electric vehicle. At present, the customers are sensitive to high pitched tonal noise produced by electric powertrain which gives a lot of challenges to NVH engineers to arrive at a cost-effective solution in less span of time Higher structure borne tonal noise is perceived in electric vehicle at the vehicle speeds of 15 kmph and 60 kmph. The test vehicle is front wheel drive compact SUV powered by motor in the front. The electric powertrain is connected to subframe with help of three mounts. Transfer path analysis (TPA) using blocked forces method is carried out to identify the exact forces of the powertrain. Powertrain mount is characterized by applying the predicted forces and dynamic stiffness at problematic frequency is measured. By reducing the dynamic stiffness of powertrain mounts, the noise levels are reduced by ~ 5

S, Nataraja moorthy, Rao, Manchi, Raghavendran, Prasath, Selvam, Ebinezer

Countermeasures for Low Frequency Boom noise Reduction in Electric Vehicle

2024-26-021401/16/2024

Electric vehicles are much quieter than IC engine powered vehicles due to less mechanical components and absence of combustion. The lower cabin noise in electric vehicles make customers sensitive to even small disturbance in vehicle. Road boom noise is one of the major concerns to which the customers are sensitive in electric vehicles. The test vehicle is a front wheel driven compact SUV powered by electric motor. In normal plain road, noise levels are acceptable but when the vehicle has been driven on coarse road, the boom noise is perceived, and the levels are objectionable. Multi reference Transfer path Analysis (MTPA) is conducted to identify the path through which maximum forces are entering the body. Based on MTPA, modifications are proposed on the suspension bushes and the noise levels were assessed. Operational deflection shape (ODS) analysis is conducted on entire vehicle components like suspension links, sub frame, floor, roof, and doors to identify the deflection pattern of

S, Nataraja moorthy, Rao, Manchi, Raghavendran, Prasath, Selvam, Ebinezer

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

Measured Vehicle Inertial Parameters - NHTSA’s Data through August 2020

2021-01-097004/06/2021

This paper is the fourth printed listing of the National Highway Traffic Safety Administration’s (NHTSA) center-of-gravity (CG) location measurements. The previous papers contained data for 1024 vehicles. This paper includes data for 448 additional vehicles tested as part of NHTSA’s New Car Assessment Program (NCAP) for the years 2009 through year 2020. The NCAP involves only the CG location measurement; so the vehicles listed in this paper do not have inertial data.

Zagorski, Scott, Heydinger, Gary, Coyle, Jon, Jebode, Mahendranauth

WHAT WE'RE DRIVING

21AUTP02_0802/01/2021

Since its U.S. launch for the '18 model year, the positioning of the Kicks has puzzled me. Though Nissan was anxious to bill it a “crossover,” I think most would call it a “car.” Nissan hardly is alone in this marketing sleight-of-hand. Given American buyers' refusal to tarnish themselves with anything that can't be construed as some kind of truck, it's at least understandable. But here's my rule: no calling it a crossover if it can't be had with all-wheel drive. And confoundingly, inexplicably, stubbornly against all sense, the Kicks is strictly front-drive. Apart from that, the Kicks probably accomplishes some of the mission of grabbing buyers who need to think they're not purchasing a car; Nissan sold a comparatively healthy 58,858 Kicks in 2020.

Definition and Measurement of Power Transfer Unit Speed-Dependent Parasitic Loss

J3039_202012 (Current)

12/30/2020

This SAE Recommended Practice covers power transfer units (PTUs) used in passenger car and sport utility vehicles to support all wheel drive (AWD) operation. PTUs are typically full-time use geared devices (see 3.1). Some PTUs have additional features such as part-time on-demand capability via electronically actuated disconnect features, and other configurations are possible.

Drivetrain Standards Committee

Research on Technique for Correction of Running Resistance with Focus on Tire Temperature and Tire Thermal Balance Model

2019-01-062304/02/2019

At present, measurements of running resistance are conducted outdoors as a matter of course. Because of this, the ambient temperature at the time of the measurements has a considerable impact on the measurement data. The research discussed in this paper focused on the temperature characteristic of the tires and developed a new correction technique using a special rolling test apparatus. Specifically, using a tire rolling test apparatus that made it possible to vary the ambient temperature, measurements were conducted while varying the levels of factors other than temperature that affect rolling resistance (load, inflation pressure, and speed). Next, a regression analysis was applied to the data for each factor, and coefficients for a relational expression were derived, making it possible to derive a quadratic equation for the tire rolling resistance correction formula. It was verified that the application of the new correction formula reduced variation in running resistance from 2.7

Hotaka, Takeshi, Sakai, Tomonori, Miura, Hideki

All-Wheel Drive Systems Classification

J1952_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

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

2018-01-041104/03/2018

Maximising the recovered regenerative braking energy during the deceleration can significantly reduce the Electric Vehicle (EV) energy consumption and increase the range. Compared with the Front Wheel Drive (FWD) or Rear Wheel Drive (RWD) EV, an All Wheel Drive (AWD) EV with 2 electric machines (e-machines) has more control degree freedom when developing the regenerative braking control strategy. By implementing the regenerative braking at the front axle, rear axle, or at the front and rear axles simultaneously, the amount of recovered kinetic energy will be affected. Furthermore, the e-machines at the front and rear axle in the AWD EV can have different sizes or be the same. Therefore, the ratio between front and rear e-machine power rating should also be investigated to understand its effect on the amount of recovered energy during deceleration. This paper starts with the analysis of the vehicle braking behaviour compared over different driving cycles, and the comparison of two

Bao, Ran, Griggs, Philip, Baxter, James

Performance Prediction of Automotive Wheel Bearing Seals

2017-01-252509/17/2017

The primary functions of bearing seals are to prevent lubrication from escaping and foreign material from entering, the effectiveness of which is determined by the design of the seal lips. Bearings with low friction rotation are in great demand in the automotive market as a direct result of enforced vehicle fuel economy and reduced CO2 emissions regulations. Therefore, bearings with good sealing function and low friction rotation are required. This makes designing a seal challenging as the ideologies of high seal-ability and low friction rotation tend to be contradictory. Current estimations of bearing seal friction or rotational torque require significant time and cost through empirical methods of trial and error. Research into the estimation of bearing rotational torque through numerical analysis, based on finite element methods, is the focal point of this paper. This development includes the calculation of bearing rotational torque using an axisymmetric model from the commercial

Lee, Seungpyo, Park, Mincheol

Optimization of Front Wheel Drive Engine Mounting System for Third Order Shudder Improvement

2017-01-917504/11/2017

Nowadays, the vehicle design is highly ruled by the increasing customer demands and expectations. In addition to ride comfort and vehicle handling, the Noise, Vibration and Harshness (NVH) behavior of the powertrain is also a critical factor that has a big impact on the customer experience. To evaluate the powertrain NVH characteristics, the NVH error states should be studied. A typical NVH event could be decoupled into 3 parts: source, path, and receiver. Take-off shudder, which evaluates the NVH severity level during vehicle take-off, is one of the most important NVH error states. The main sources of Front Wheel Drive (FWD) take-off shudder are the plunging Constant Velocity Joints (CVJ) on the left and right half shafts. This is because a plunging CVJ generates a third order plunging force with half shaft Revolution Per Minute (RPM), which is along the slip of the plunging CVJ. The primary path of take-off shudder is the Engine Mounting System (EMS), which isolates the vibration

Zhu, Yitao, Addepalli, Kalyan, Remisoski, Natalie, Datar, Makarand

Study of Power Hop on Front Wheel Drive Vehicles Influence of Mounts, Driveline, Tires and Wheels

2016-36-017210/25/2016

This paper has the objective to present the study made on a front wheel drive passenger car with “3 Points Pendular Mounts System” to minimize the “Power Hop effect” (powertrain forced oscillation) and reduce the loads on Powertrain Mounts System. In this study, we used the Taguchi Method (Design of Experiments) to optimize the number of tests performed to evaluate the influence of powertrain mounts system design characteristics, as well as axle shafts stiffness, and tire/wheels assemblies size. The data acquisition work was all done in a physical hardware (vehicle) on test track used instrumented parts and load cells. Accelerometers were used in previous tests to get qualitative understanding of the behavior of all interface components (mounts and wheels hubs) during the power hop event. The study results showed the best components combination in order to reduce peak loads over Powertrain System and, as a consequence, reducing the potential of components breakage under extreme

Amparo, João Fernando Mendes, Barbetti, Marcos Rogério Santos, Zavala, Paulo Alexandre Galarce, Ballardie, George, Moriya, Roberto

The New Generation Front Wheel Drive Hybrid System

2016-01-116704/05/2016

Introducing all-new front wheel drive hybrid system installed in the 2016 Toyota Prius. This system was completely re-designed to maximize the potential of THS-II (Toyota Hybrid System-II). This system was designed to be able to minimize the mechanical and electrical losses from the previous generation system, improve environmental performance, and also tried to reduce size and weight. We’d like to take this opportunity to introduce the new technology of each component, and hybrid system performance.

Fushiki, Shunsuke

Gear Fault Diagnosis Based on Optimal Morlet Wavelet Filter and Autocorrelation Enhancement

2015-01-021204/14/2015

An efficient condition monitoring system provides early warning of faults by predicting them at an early stage. When a localized fault occurs in gears, the vibration signals always exhibit non-stationary behavior. The periodic impulsive feature of the vibration signal appears in the time domain and the corresponding gear mesh frequency (GMF) emerges in the frequency domain. However, one limitation of frequency-domain analysis is its inability to handle non-stationary waveform signals, which are very common when machinery faults occur. Particularly at the early stage of gear failure, the GMF contains very little energy and is often overwhelmed by noise and higher-level macro-structural vibrations. An effective signal processing method would be necessary to remove such corrupting noise and interference. In this paper, a new hybrid method based on optimal Morlet wavelet filter and autocorrelation enhancement is presented. First, to eliminate the frequency associated with interferential

El Morsy, Mohamed, Achtenova, Gabriela

Vibration Reduction in Motors for the SPORT HYBRID SH-AWD

2015-01-120604/14/2015

A new motor has been developed that combines the goals of greater compactness, increased power and a quiet drive. This motor is an interior permanent magnet synchronous motor (IPM motor) that combines an interior permanent magnet rotor and a stator with concentrated windings. In addition, development of the motor focused on the slot combination, the shape of the magnetic circuits and the control method all designed to reduce motor noise and vibration. An 8-pole rotor, 12-slot stator combination was employed, and a gradually enlarged air gap configuration was used in the magnetic circuits. The gradually enlarged air gap brings the centers of the rotor and the stator out of alignment, changing the curvature, and continually changing the amount of air gap as the rotor rotates. The use of the gradually enlarged air gap brings torque degradation to a minimum, and significantly reduces torque fluctuation and iron loss of rotor and stator. A superposed harmonic current is used as the control

Transmission Dynamic Modeling and Parametric NVH Analysis

2015-01-114704/14/2015

A new approach for modeling and analysis of a transmission and driveline system is proposed. By considering the stiffness, damping and inertias, model equations based on lumped parameters can be created through standard Lagrangian Mechanics techniques. A sensitivity analysis method has then been proposed on the eigenspace of the system characteristic equation to reveal the dynamic nature of a transmission and driveline system. The relative sensitivity calculated can clearly show the vibration modes of the system and the key contributing components. The usefulness of the method is demonstrated through the GM 6-speed RWD transmission by analyzing the dynamic nature of the driveline system. The results can provide a fundamental explanation of the vibration issue experienced and the solution adopted for the transmission. The proposed method can greatly simplify the NVH related analysis, which is useful for architecture selection, shift dynamic analysis, TCC damper design, driveline

Beyond Driveline Disconnect - The Ultimate On-Demand Dry Sump RDM System with PTU Disconnect

2015-01-109904/14/2015

Recent developments in front wheel drive based all-wheel drive (AWD) systems have focused on the disconnection of the secondary driveline to provide a high efficient 2-Wheel Drive (2WD) mode in order to minimize parasitic losses and increase fuel economy when all-wheel drive is not required. This present study compares a base on-demand all-wheel drive system without disconnect features to one with disconnect features in the rear drive module (RDM) and power transfer unit (PTU) to fully disconnect the secondary drive line. In order to further reduce parasitic losses the RDM also utilized an on-demand lubrication system. In conjunction with the active lubrication system, the oil sump level was reduced to assure all clutch housings and their associated plates were above the oil level at all times in order to minimize shear losses. Positive plate separation was also employed to assure ample clearance for free-running clutch plates. Essentially, the tested disconnect system represents the

Kopp, Thad, Pritchard, Larry A.

Fault Diagnosis of Rolling Bearing Based on Time Waveform Analysis

2015-01-167104/14/2015

In this paper, a fault in rolling bearing is diagnosed using time waveform analysis. In order to verify the ability of time waveform analysis in fault diagnosis of rolling bearing, an artificial fault is introduced in vehicle gearbox bearing: an orthogonal placed groove on the inner race with the initial width of 0.6 mm approximately. The faulted bearing is a roller bearing located on the gearbox input shaft - on the clutch side. An optimal Morlet Wavelet Filter and autocorrelation enhancement are applied in this paper. First, to eliminate the frequency associated with interferential vibrations, the vibration signal is filtered with a band-pass filter determined by a Morlet wavelet whose parameters are optimized based on maximum Kurtosis. Then, to further reduce the residual in-band noise and highlight the periodic impulsive feature, autocorrelation enhancement is applied to the filtered signal. The proposed techniques are used respectively to analyze the experimental signal of vehicle

El Morsy, Mohamed, Achtenova, Gabriela

Analysis of Drive Line Vibration and Boom Noise in an All Wheel Drive Utility Vehicle

2014-01-197504/01/2014

The customer demand for all wheel drive (AWD) vehicles is increasing over the period of time which also requires NVH performance on par with front wheel drive vehicles. AWD vehicles are equipped with power transfer unit, propeller shaft and independent rear differential assembly to achieve their functional requirement. The additional drive train components in AWD vehicles may amplify torsional fluctuations in the drive line. Hence achieving the NVH performance of AWD vehicles on par with FWD vehicles without any major change in the existing design is a major challenge. In this work, an AWD vehicle with severe body vibration and booming noise is studied. The operational measurements are taken throughout the drive train on all sub-systems from engine to the rear part of the body in the problematic operating condition. An operational deflection shape analysis is conducted to visualize the vibration behavior of the drive train. The result of analysis shows that the dynamic torsional

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

Development of Jatco CVT8 Hybrid for Infiniti JX and Nissan Pathfinder

2014-01-178804/01/2014

Conflicting customer demands for reduction of CO2 emissions (fuel economy improvement) and enhancement of driving pleasure are continuing to become more rigorous all the time. Against this backdrop, JATCO launched the transmission for hybrid system with Nissan in 2010, followed by the development of a hybrid system for use on a front-wheel-drive midsize SUV in the North American market. Among the various types of hybrid systems proposed to date, this one-motor two-clutch (1M2CL) parallel hybrid system achieves high efficiency with no engine friction loss during the EV mode and energy regeneration. This paper describes the new Jatco CVT8 HYBRID (CVT8 HYBRID), it is newly developed packaging technologies for compactly mounting the 1M2CL parallel hybrid system on front-wheel-drive vehicles.

Osone, Tatsuya, Seiji, Terauchi, Yamamoto, Takeshi, Konagaya, Fumihito

Development of High Torque Capacity Variator System for CVT

2014-01-172904/01/2014

The new Jatco CVT8 High Torque (CVT8 HT) was developed for use on front-wheel-drive vehicles fitted with a large displacement engine. The development objectives set for this new CVT with a high torque capacity were outstanding fuel economy, size and weight reductions. To achieve those targets, a high torque capacity CVT chain was newly developed in cooperation with LuK GmbH & Co. KG. This article describes the efforts undertaken to develop increasing torque capacity.

Soya, Hiromu, Yoshida, Makoto, Imai, Kazutaka, Miura, Yoshitaka, Matsushita, Yuuki

Electric Drive System for SPORT HYBRID SH-AWD

2014-01-182104/01/2014

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

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 and Analysis Drive Transmission Development

TBMG-1720709/01/2013

Vicura is a developer of manual transmissions and dry dual clutch transmissions, as well as powertrain integration in a large number of front wheel drive and all wheel drive applications. The company’s engineers are responsible for a broad range of complex simulation and analysis testing including system, structure, and fluid mechanics. The team performs critical simulation and analysis to ascertain the strength, stiffness, thermal, and dynamic behaviors of all possible transmission assemblies and components (housings, shafts, gears, synchronizers, clutches, etc.).

Development of a Standard Spin Loss Test Procedure for FWD-Based Power Transfer Units

2013-01-036104/08/2013

As vehicle fuel economy continues to grow in importance, the ability to accurately measure the level of efficiency on all driveline components is required. A standardized test procedure enables manufacturers and suppliers to measure component losses consistently and provides data to make comparisons. In addition, the procedure offers a reliable process to assess enablers for efficiency improvements. Previous published studies have outlined the development of a comprehensive test procedure to measure transfer case speed-dependent parasitic losses at key speed, load, and environmental conditions. This paper will take the same basic approach for the Power Transfer Units (PTUs) used on Front Wheel Drive (FWD) based All Wheel Drive (AWD) vehicles. Factors included in the assessment include single and multi-stage PTUs, fluid levels, break-in process, and temperature effects. The resultant procedure is proposed as a new SAE J-standard (Surface Vehicle Recommended Practice) for release by the

Kirk, Michael P., D'Anna, Thomas, Seldon, William, Perakes, Andreas, Ross, Craig

The Design, Development and Industrialization of an New 8 Speed Automatic Transmission in China

2013-01-127704/08/2013

Shengrui Transmission Limited Corporate (Shengrui) has developed a new 8 speed automatic transmission (SR 8AT) for front wheel drive (FWD) vehicle. The concept of SR 8AT is unique and different from the conventional automatic transmission. The design of the SR 8AT system and components are new and compact. By combining an innovative gear train which is similar with the conventional manual transmission and the simple planetary gear structure, SR 8AT achieved 8 speed with the shortest length of the FWD transmission, the competitive fuel economy and the smooth shift performance among comparable automatic transmissions.

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

2013-01-123504/08/2013

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

Development of a Standard Spin Loss Test Procedure for 4WD Transfer Cases

2012-01-030604/16/2012

As vehicle fuel economy continues to grow in importance, the ability to accurately measure the level of parasitic losses on all driveline components is required. A standardized comparison procedure enables manufacturers and suppliers to measure component losses consistently, in addition to offering a reliable process to assess enablers for efficiency improvements. This paper reviews the development of a comprehensive test procedure to measure transfer case speed-dependent parasitic losses at key speed, load, and environmental conditions. This procedure was validated for repeatability considering variations in soak time, temperature measurement positions on the transfer case, and test operating conditions. Additional assessments of spin loss at low ambient temperatures, and the effect of component break-in on spin loss were also conducted. The resultant procedure is proposed as a new SAE J-standard (Surface Vehicle Recommended Practice J2985) for release by the All Wheel Drive (AWD

Kirk, Michael, Ilyas, Syed M., D'Anna, Thomas, Perakes, Andreas E., Ross, Craig S.

Driveline Boom Interior Noise Prediction Based on Multi Body Simulation

2011-01-155605/17/2011

It is important to develop powertrain NVH characteristics with the goal of ultimately influencing/improving the in-vehicle NVH behavior since this is what matters to the end customer. One development tool called dB(VINS) based on a process called Vehicle Interior Noise Simulation (VINS) is used for determining interior vehicle noise based on powertrain level measurements (mount vibration and radiated noise) in combination with standardized vehicle transfer functions. Although this method is not intended to replace a complete transfer path analysis and does not take any vehicle specific sensitivity into account, it allows for powertrain-induced interior vehicle noise assessments without having an actual test vehicle available. Such a technique allows for vehicle centric powertrain NVH development right from an early vehicle development stage. While this is a proven tool for powertrain level sound quality evaluations and correlates well for front wheel drive (FWD) vehicles, the interior

Wellmann, Thomas, Govindswamy, Kiran, Eisele, Georg

Annular Nozzle in Fixed Displacement Transmission Pump

2011-01-072304/12/2011

General Motor's new front wheel drive six speed 6T40 automatic transmission benefits from patented technology to control high speed pump cavitation that is innovative yet cost effective. An annular nozzle is created with careful pump inlet design by integrating a conical section in the filter neck to create a jet pump to prevent high speed cavitation for almost no additional cost. Excess oil from a fixed displacement pump is used to achieve an effective increase in pressure at the inlet of the rotating group during high speed operation. Control of high speed cavitation reduces pump noise and improves line pressure control stability.

Prospects for Future 4WD and AWD Developments for Pick Ups, SUVs and Passenger Cars in Brazil

2010-36-047910/06/2010

The purpose of this paper is to present the origins and the technology of the different types of AWD (All Wheel Drive) and 4WD (Four Wheel Drive) systems currently available and the wide potential to incorporate such technologies to the vehicles made in Brazil. In the Brazilian market the 4WD and AWD vehicle options are available only on expensive pickups and imported SUVs, which include only a small part of the total market. Conversely, there are a large number of 4WD & AWD technologies available in developed markets that are not currently available in the South American markets. Most South American consumers regard vehicles with 4WD/AWD systems as off-road vehicles to be driven in the countryside, in an off-road environment. These markets still don`t have a clear understanding of the differences between 4WD and AWD, and the benefits of each. This paper will describe the concepts, the architecture and the operations of such systems and point out the correct application of each ones

Neto, Demetrio Vettorazzo, Fornari, Rafael, Rupcic, Jorge, Suzuki, Alexandre

Power Electronics for GM 2-Mode Hybrid Electric Vehicles

2010-01-125304/12/2010

General Motors has developed a portfolio of advanced propulsion vehicles that has set the standard for optimal fuel economy in full-size utility vehicles. An overview of power electronics used in this portfolio, already available in the market, is presented. These components are key enablers for the strategic products in portfolio. Block diagrams for various configurations are also described to show common power electronics components used in traction and auxiliary systems. Briefly real wheel drive (RWD) and front wheel drive (FWD) vehicle applications are described. Specific analysis and test results are presented from development of Traction Power Inverter used in RWD vehicles. Vehicle-based durability profiles are used in analysis to predict IGBT power modules thermal performance. Using key metrics for volume and mass, benchmarking data is also presented.

Desai, Prakash H., Anwar, Mohammad, Gleason, Sean, Hawkins, Shawn

General Motors Small Front Wheel Drive Six speed Automatic Transmission Family

2010-01-085704/12/2010

General Motors introduced a family of small front wheel drive six speed automatic transmissions for the 2008 model year. The family currently has two variants: 6T40 and 6T45, which cover a range of vehicles from small & compact cars to small SUVs and handle engines torque capacities up to 240 Nm Gas(280 Nm Diesel) & 315 Nm Gas (380 Nm Diesel) respectively. The 6T40/45 transmissions replace GM traditional four speed automatic wrap around transmissions 4T40/45. The wrap around transmissions have Torque Converter, Pump & Controls on the engine axis and the rest of the transmission content on the output axis. The 6T40/45 have an on-axis architecture with majority of the transmission content on the engine axis and final drive & differential on the output axis. The 4T40/45 have input chain transfer whereas the 6T40/45 have an output chain transfer. The objectives behind the creation of the 6T40/45 transmissions were improved fuel economy, performance, mass and NVH as compared to the

Singh, Tejinder, Olenzek, Richard

Development of a Compact Torque Vectoring Axle for Primary or Secondary Axles

2008-01-030504/14/2008

There has been a recent demand for torque vectoring axles in premium sedans and high end sports vehicles. The improved handling and active safety resulting from this product is desirable in all vehicles. As the cost of these units is driven down, the applications should proliferate to lower cost vehicles. This paper is to introduce a torque vectoring axle assembly designed for low cost manufacturing methods to allow this proliferation.

Aspects of Driveline Integration for Optimized Vehicle NVH Characteristics

2007-01-224605/15/2007

Customer requirements for quiet and more comfortable vehicles have steadily increased. Requirements for lightweight vehicle designs and the need for more fuel efficient engines are often contradictory to the customer expectations for NVH refinement. The driveline can be a significant source of NVH issues in the vehicle. The increasing complexity of modern driveline systems as well as the existence of several variants in the driveline architecture (front wheel, rear wheel and four-wheel/all-wheel drive, automatic-, manual-, automatic-shifted manual transmission, etc.) can make the driveline integration task very challenging. Due to the multitude of driveline components and potential driveline excitations sources, several driveline-related noise and vibration problems within different frequency ranges have to be understood and controlled to ensure a well refined vehicle. It is important for the integration process to understand that a design modification to the driveline can have an

Wellmann, Thomas, Govindswamy, Kiran, Braun, Eugen, Wolff, Klaus

Estimation of Powertrain Inertia Properties via an In-situ Method

2007-01-241005/15/2007

An experimental method has been developed which allows the rigid body inertia properties of an automotive type powertrain to be estimated in-situ without removing the powertrain from the vehicle. The method requires that the complex stiffness properties of the powertrain mounts be estimated therefore allowing through the measurement of the relative displacements across the mounts for the estimation of the forces generated at the powertrain mount locations. Rigid body motion measurements are made through the use of accelerometers simultaneous to exciting the powertrain with multiple shakers. Results of the method are compared to those acquired through an inertia pendulum and the FRF based method implemented in LMS Cada-X software. Effects on the results due to shaker location, response location, mount variation, and removal of powertrain peripherals are also investigated. The method is validated through both an actual vehicle's powertrain estimation as well as through the testing of a

Van Karsen, Jeffrey, Johnson, David, Blough, Jason, Rao, Mohan, Ge, Tony

The Influence of Rotating Wheels on Total Road Load

2007-01-104704/16/2007

Within in the scope of a road load investigation project at FKFS, the influence of rotating wheels on the road load of a passenger car was investigated. For this purpose an approach was developed to measure the ventilation resistance of a spinning wheel. This approach enables a comparison of different wheel sizes and rim designs. Together with aerodynamic drag measurements in the wind tunnel it is possible to evaluate different wheel configurations with respect to their contribution to the road load. The measuring approach and results of performed measurements are shown in this paper.

Mayer, Wolfgang, Wiedemann, Jochen

Development of NexTrac™ Electronic Driveline Coupling for Front-Wheel Drive Based All-Wheel Drive Applications

2007-01-066004/16/2007

There is a significant market shift taking place between RWD and FWD based AWD segments. The industry is experiencing a tremendous growth of FWD based AWD with the majority of new FWD platforms offering an AWD derivative. This has created demand for higher performing, cost effective, electronically controlled on-demand AWD couplings. To meet this demand BorgWarner, has developed a new electronically controlled driveline coupling called NexTrac™. NexTrac™ is a significant departure from conventional electro-magnetically actuated FWD/AWD couplings prevalent in the market today. The most distinct new feature is the direct actuation of the primary clutch by an electro-mechanical system using organic friction material for the primary clutch plates instead of steel. This, and other features give NexTrac superior lifetime NVH performance and cost effective driveline integration.

Barlage, John, Mastie, Joseph, Niffenegger, Donn

Design of the World's Fastest E1 Class Electric Car

2006-01-366712/05/2006

World speed racing is perhaps the pinnacle of all racing. At Brigham Young University, a team of students designed an E1 class car using computer-aided design and analysis. Advanced batteries were tested under extremely fast discharge to determine their suitability for racing. A test frame was also manufactured by the students, and preparations are beginning to race on the Utah Salt Flats.

Baxter, Jeffrey

Development of a Super-Flat Torque Converter for the New Toyota FWD 6-Speed Automatic Transaxle

2006-01-014904/03/2006

Toyota Motor Corporation has developed a new super-flat torque converter for the Flex Start System. It is installed in a new six-speed automatic transaxle (U660E) for front engine, front wheel drive vehicles. The Flex Start System is the first technology in the world that can start smoothly and reduce torque converter slipping loss by using a lock-up clutch at start. The newly developed super-flat torus achieves a high torque capacity and a maximum efficiency of 90%. Fuel economy is increased further by adding an efficient damper for low-speed lock-up in the free space provided by utilizing the super-flat torus. Toyota also developed a simple and super-flat structure at the one-way clutch (O.W.C.) area. This paper describes the structure, features, and performance of this new torque converter and the Flex Start System.

Ochi, Toru, Takeuchi, Hiroaki, Kimura, Hiromichi, Watanabe, Kazuyuki

Quantifying the Change in Ride Height Due to Braking: Brake Dive Test Data

2006-01-156304/03/2006

The concept of brake dive is not new and most drivers are aware of this phenomenon. However, no known data is available to quantify the amount of change in vehicle height during braking. Often investigators involved in under-ride/over-ride collisions or relatively low speed collisions are faced with questions such as, “How much does the front bumper dip during braking?” or, “Is it likely that the relative bumper height mismatch is due to pre-impact braking?” This paper will provide the results of field testing aimed at providing answers to these and associated questions. The study will also review the factors that affect brake dive and the parameters under which these factors can be determined or be reasonably estimated. We consider how these factors can be used to predict the amount of change in bumper height.

Ray, Shawn P., Newbery, Trevor M., Koziol, John A.

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

2006-01-056004/03/2006

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

Force and Moment Characteristics of Two Space-Saver Tires

2006-01-155904/03/2006

Many modern vehicles utilize so-called “space-saver” spare tires. Such tires are not fitted to the vehicle and driven on until a tire problem has arisen with a service tire, and are limited in the mileage and speed at which they can operate. They also may have quite different characteristics (rolling radius, tread pattern, contact patch width and length, aspect ratio, stiffnesses, self-aligning torques, etc.) than the service tires with which the vehicle is equipped. As such, they have the potential for presenting significantly different handling signatures to the driver when they are fitted.. In the present work, we present force and moment characteristics for two disparate space-saver spare tires. The tires were tested at the T.I.R.F. (TIre Research Facility), Calspan Corporation, Buffalo, NY. Using the data obtained from the experimental tire test program, under-steer gradients (UG) were calculated for two vehicles typical of those that would employ each respective tire (sports car

Evaluating The Rolling Contact Fatigue Properties Of Surface Densified PM Gears

2006-01-039504/03/2006

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

Getting validation

AUTOAPR06_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.

Steer-by-Wire System for Micro Electric Vehicle

2005-32-000410/12/2005

It is intended in this study to use the in-wheel electric motors for the traction of the micro electric vehicle as the actuator for the steer-by-wire as well. Both right and left front suspensions of the front wheel drive electric vehicle have some large enough kingpin offsets in lateral direction and once the traction torques according to the steer command are applied to the both in-wheel motors in opposite direction each other, the front wheels are to be steered to control the vehicle. The experimental vehicle provided by this steering system is developed in order to prove experimentally how the simultaneous use of the motors for the traction and the steering for the steer-by-wire in the micro electric vehicle is available. The responses of the steering system and the electric vehicle to several steer inputs are investigated to find out the effects of the design parameters of the system on the steering characteristics. The results show that it is practically possible to use the

SAITO, Yohei, KANO, Yoshio, ABE, Masato

Order Separation Using Multiple Tachometers and the TVDFT Order Tracking Method

2005-01-226505/16/2005

An automobile and a tracked military vehicle were instrumented with multiple tachometers, one for each drive wheel/sprocket and operated with accelerometers mounted at suspension, chassis, and powertrain locations on the vehicles. The Time Variant Discrete Fourier Transform, TVDFT, order tracking method was then used to extract the order tracks and operating shapes estimated based on each tachometer. It is shown that under some conditions a different operating shape is excited by each of the wheels/sprockets simultaneously. This is due to the asymmetries present in the vehicles. The strengths of the TVDFT order tracking method are shown for this type of analysis, which is difficult due to the closeness, within 0.001 orders, and crossing of the orders. Benefits of using multiple tachometers and advanced order tracking methods become apparent for solving a class of noise and vibration problems.

Blough, Jason R.

Effect of an Optimized Heatshield Design and an Aerodynamic Exhaust Tunnel Cover on Convective Heating of the Floor Pan

2005-01-201605/10/2005

A thermal investigation based on measurements on 3 different front wheel driven vehicles has been carried out. Temperatures were recorded on road and test bench and showed the potential to improve the thermal protection in the area of the exhaust line tunnel. This improvement can be achieved by design changes on the tunnel heatshield, which prevent convective heating of the body. Compared to the respective baseline conditions temperatures at the tunnel body were lowered by 15°C on average and in some regions by more than 40°C. The investigation shows the potential of closing the tunnel area underneath the exhaust line for improving aerodynamic drag while keeping temperatures of the tunnel body and sensitive components at an acceptable level.

de Ciutiis, Hermann

Dynamic Modeling and Simulation of Front Wheel Drive Drag Cars

2005-01-042104/11/2005

This paper discusses the development of several models and accompanying results for the simulation of the longitudinal and vertical dynamics of a front wheel drive drag car. Models developed include provisions for wheelie bar, chassis flexibility, and anti-squat geometry. The simulation computes quarter-mile times and speeds for various combinations of input parameters. It allows for the analysis of the various factors that affect steady state axle loads and dynamic load transfer, their effects on traction, and the resulting quarter-mile times. Results of case studies examine specific vehicle components and parameters and their effects on performance. These include the wheelie bar, wheel rates, anti-squat properties, and chassis flexibility.

Knauff, Michael D., Law, E. Harry

Physical System Model of a Hydraulic Energy Storage Device for Hybrid Powertrain Applications

2005-01-081004/11/2005

The chemical storage battery is currently the primary choice of automotive powertrain designers for hybrid-electric vehicles. This design suffers from complexity, manufacturing, cost, durability, poor performance predictability and other problems. Additionally, the trend in hybrid powertrain design is to move from high energy density to high power density. A proposed alternative to chemical batteries for some hybrid vehicle applications is an electro-mechanical battery (EMB) that combines an electric machine with hydro-pneumatics to provide energy capture, storage, and propulsion assistance. An initial multi-domain physical system model of an EMB-based hybrid powertrain has been developed in the Simulink environment to show the behavior of the EMB design in a midsize hybrid passenger vehicle application.

Jackey, Robyn A., Smith, Paul, Bloxham, Steven

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