Browse Topic: Front wheel drive

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Comprehensive Analysis and Mitigation Strategies to minimize torque Steer phenomenon for FWD vehicles during the vehicle development2026-26-0097To be published on 01/16/2026
Born Electric SUVs is gaining immense popularity due to enhanced ride and handling characteristics, advanced tech features elevating both performance and customer experience to an elite standard. Due to the platform constraints, the vehicle adopts a Front Wheel Drive (FWD) layout with a rear twist beam configuration, housing the electric motor at the front to deliver drive torque directly to the front wheels. Torque steer is a phenomenon often found in FWD cars, which can be unsettling to a driver where the steering wheel could be pulled hard to one side when there is aggressive throttle input potentially leading to deviation of the vehicle from its desired path. In contrast to internal combustion engines (ICEs), electric motors provide an instantaneous torque, something that can worsen torque steer if not well addressed. However, torque steer remains a key concern, with high torque output of electric motors especially for a front wheel drive vehicle. This paper introduces a
PRABHAKARA RAO, VAGEESH, Wankhade, Krishna, Thakur, Pragyesh, Rasal, Shraddhesh, Asthana, Shivam
Countermeasures for Low Frequency Boom noise Reduction in Electric Vehicle2024-26-021401/16/2024
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
NVH Refinement of Structure borne tonal noise in electric vehicle2024-26-019801/16/2024
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
Analysis and Reduction of Abnormal Suspension Noise in Sports Utility Vehicle2024-26-021701/16/2024
This paper focuses on reducing abnormal noise originating from suspension when driving on rough road at the speed of 20 kmph. The test vehicle is a front wheel driven monocoque SUV powered by four cylinder engine. Cabin noise levels are higher between 100 to 800 Hz. Vibration levels are measured on front and rear suspension components, front and rear subframe, subframe connections on body to identify the noise source locations. Since the noise levels are dominant only in certain rough patches at very narrow band of time, wavelet analysis is used for problematic frequency identification. Based on wavelet analysis, it is identified that the vibration levels are dominant on front lower control arm (LCA) due to inferior isolation performance. The dynamic stiffness of LCA bushes is reduced by ~ 30% to improve the isolator performance which reduced the noise levels by ~ 2 dB (A). Modal analysis is conducted on suspension components like LCA, stabiliser bar, shock absorber, tires and front
S, Nataraja Moorthy, Rao, Manchi Venkateswara, Raghavendran, Prasath, Manivannan, Giridharan
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
WHAT WE'RE DRIVING21AUTP02_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 LossJ3039_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
Validation of Telemetry Data Acquisition Using GoPro Cameras2020-01-087504/14/2020
Several GoPro camera models contain Global Positioning System (GPS), accelerometer, and gyroscope instrumentation and are capable of measuring and recording position, velocity, acceleration, and inertial data. This study evaluates the accuracy of data obtained from GoPro cameras through a series of controlled tests. A test vehicle was instrumented with a Racelogic VBOX data acquisition unit as well as various generations of GoPro camera units equipped with GPS capability and driven on a road course. The raw data collected with the GoPro cameras and the translations of this data provided by the GoPro Quik desktop software application were compared to data collected with the validated VBOX data acquisition unit. The results demonstrated that position, velocity, and acceleration data recorded with GoPro cameras is consistent with VBOX data and is useful for applications related to accident reconstruction.
Petroskey, Karla, Funk, Charles, Tibavinsky, Ivan A.
Testing Methods and Signal Processing Strategies for Automatic Transmission Transient Multiplexed Pressure Data2019-01-150006/05/2019
Transmissions have multiple transient events that occur from gear shifting to torque converter clutch application. These transients can be difficult to capture and observe. A six speed front wheeled drive transmission was instrumented with pressure transducers to measure clutches and the torque converter. Due to size restrictions internal to the torque converter the data had to be multiplexed across three different transmitters. A method to capture a transient event through the use of multiplexed data was developed to create a data set with the transient event occurring on each channel. Once testing is completed, the data has to be split into individual channels and synced with the operational data. The data then can be used in both time and frequency domain analysis. It is important to understand that the data is not continuous and must be taken into consideration when post processing it for further results.
Woodland, Mark, Blough, Jason, Robinette, Darrell, Anderson, Carl, Frait, Steve, Devendran, Ram Sudarsan
Research on Technique for Correction of Running Resistance with Focus on Tire Temperature and Tire Thermal Balance Model2019-01-062304/02/2019
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
WHAT WE'RE DRIVING18AUTP10_0510/01/2018
Mercedes-Benz is fond of saying it cascades at least some of the S-Class' posh luxury and technology throughout its range. That's just what it has done for the fourth-generation A-Class, the nameplate that sits at the bottom of the brand's lineup. The new A-Class is heaped with cabin tech, in particular. Built on Mercedes' MFA2 front-wheel-drive platform, the A200 AMG Line version driven is well-connected, having the MBUX (Mercedes-Benz User Experience) touchscreen interface (and a touchpad), plus “Hey Mercedes” voice recognition.
Ford details more platform consolidation18AUTP09_0709/01/2018
Ford said it plans to merge today's nine global platforms to five flexible vehicle architectures with a strong emphasis on sharing modules. The automaker's revised product development process is predicted to push down the average age of its vehicles from the current 5.7 years to 3.3 years in 2020. One twist is that as new Ford products reach global markets faster, engineers won't be devoting much time to reinventing vehicle sub-system modules.
Buchholz, Kami
Explanation for Variability in Lower Frequency Structure-Borne Noise and Vibration: Roles of Rear Subframe Dynamics and Right-Left Spindle Phasing10-02-01-000205/17/2018
This investigation focuses on a class of rear suspension systems that contain both direct and intersecting structural paths from the tire contact patches to the vehicle body. The structural paths intersect through a dynamically active rear subframe structure. New experiments and computational models are developed and analyzed in this article to investigate the variability of structure-borne noise and vibration due to tire/road interactions in the lower- to mid-frequency regimes. Controlled operational experiments are conducted with a mass-production minivan on a chassis dynamometer equipped with rough road shells. Unlike prior literature, the controlled experiments are analyzed for run-run variations in the structure-borne noise up to 300 Hz in a single vehicle to evaluate the nature of excitations at the spindle as the key source of variation in the absence of significant manufacturing, assembly and instrumentation errors. Further, a deterministic modal expansion approach is used to
Noll, Scott, Singh, Rajendra
All-Wheel Drive Systems ClassificationJ1952_201804 (Current)04/18/2018
In this SAE Recommended Practice, attention will be given to passenger cars and light trucks (through Class III).
Drivetrain Standards Committee
Simulation Based Control Strategy Design of All Wheel Drive Electric Vehicle Regenerative Braking System2018-01-041104/03/2018
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 Seals2017-01-252509/17/2017
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
An Artificial Neural Network Model to Predict Tread Pattern-Related Tire Noise2017-01-190406/05/2017
Tire-pavement interaction noise (TPIN) is a dominant source for passenger cars and trucks above 40 km/h and 70 km/h, respectively. TPIN is mainly generated from the interaction between the tire and the pavement. In this paper, twenty-two passenger car radial (PCR) tires of the same size (16 in. radius) but with different tread patterns were tested on a non-porous asphalt pavement. For each tire, the noise data were collected using an on-board sound intensity (OBSI) system at five speeds in the range from 45 to 65 mph (from 72 to 105 km/h). The OBSI system used an optical sensor to record a once-per-revolution signal to monitor the vehicle speed. This signal was also used to perform order tracking analysis to break down the total tire noise into two components: tread pattern-related noise and non-tread pattern-related noise. The spatial tread pattern profile of each tire was digitized and quantified using two spectral parameters: the tread profile spectrum characterizing the tread
Li, Tan, Burdisso, Ricardo, Sandu, Corina
Value of Optimal Wavelet Function in Gear Fault Diagnosis2017-01-177106/05/2017
Gear fault diagnosis is important in the vibration monitoring of any rotating machine. When a localized fault occurs in gears, the vibration signals always display non-stationary behavior. In early stage of gear failure, the gear mesh frequency (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. This paper presents the value of optimal wavelet function for early detection of faulty gear. The Envelope Detection (ED) and the Energy Operator are used for gear fault diagnosis as common techniques with and without the proposed optimal wavelet to verify the effectiveness of the optimal wavelet function. Kurtosis values are determined for the previous techniques as an indicator parameter for the ability of early gear fault detection. The comparative study is applied to real vibration signals. First, to eliminate the frequency
El morsy, Mohamed, Achtenova, Gabriela
A Study on Reducing Gear Rattle Noise Based on Sensitivity Analysis of Drivetrain Torsional Model2017-01-177906/05/2017
With drastically reduction of engine noise, the gear rattle noise generated by the impact between neutral gears inside transmission can be much easily perceived. It is well known that the torsional mode has a direct relationship with the transmission gear rattle noise. This paper establishes a torsional model of a front wheel drive automotive drivetrain, including clutch system, transmission box and equivalent load of a full vehicle, in AMESim software. The experimental engine speed fluctuations at different gears are used to excite the torsional model. The influences of several parameters, including flywheel inertia, clutch stiffness, clutch hysteresis and drive shaft stiffness, on the 2nd order (major engine firing order for a 4-cylinder-4-stroke engine) torsional resonant frequency and the 2nd order torsional resonant peak of the transmission input shaft are analyzed by changing them alternatively. The model is validated by a comparison between the simulated and measured 2nd
Yang, Xianwu, Pang, Jian, Wang, Lanjun, Tian, Xiong, Tang, Yu
Optimization of Front Wheel Drive Engine Mounting System for Third Order Shudder Improvement2017-01-917504/11/2017
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
Deceleration Rates of Vehicles with Disabled Tires2017-01-142703/28/2017
Tire disablement events can cause a drag force that slows a vehicle. In this study, the magnitude of the deceleration was measured for different phases of 29 high speed tire tread separation and air loss tests. These deceleration rates can assist in reconstructing the speed of a vehicle involved in an accident following a tire disablement.
Koch, Daniel, Beauchamp, Gray, Pentecost, David
Optimal Tire Force Control & Allocation for Longitudinal and Yaw Moment Control of HEV with eAWD Capabilities2017-01-155803/28/2017
Hybrid Electric Vehicles (HEV) offer improved fuel efficiency compared to their conventional counterparts at the expense of adding complexity and at times, reduced total power. As a result, HEV generally lack the dynamic performance that customers enjoy. To address this issue, the paper presents a HEV with eAWD capabilities via the use of a torque vectoring electric rear axle drive (TVeRAD) unit to power the rear axle. The addition of TVeRAD to a front wheel drive HEV improves the total power output. To further improve the handling characteristics of the vehicle, the TVeRAD unit allows for wheel torque vectoring at the rear axle. A bond graph model of the proposed drivetrain model is developed and used in co-simulation with CarSim. The paper proposes a control system which utilizes tire force optimization to allocate control to each tire. The optimization algorithm is used to obtain optimal tire force targets to at each tire such that the targets avoid tire saturation. The Youla
Velazquez Alcantar, Jose, Assadian, Francis, Kuang, Ming
Study of Power Hop on Front Wheel Drive Vehicles Influence of Mounts, Driveline, Tires and Wheels2016-36-017210/25/2016
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 System2016-01-116704/05/2016
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
NVH Analysis of Powertrain Start/Stop Transient Phenomenon by using Wavelet Analysis and Time Domain Transfer Path Analysis2015-01-229306/15/2015
Tactile vibration during vehicle key on/off is one of the critical factors contributing to the customer perceived quality of the vehicle. Minimization of the powertrain transient vibration in operating conditions such as key on/off, tip in/out and engagement/disengagement of engine in hybrid vehicles must be addressed carefully in the vehicle refinement stage. Source of start/stop vibration depends on many factors like engine cranking, engine rpm at which the combustion process starts and rate of engine rpm rise etc. The transfer path consists of elastomeric mounts of powertrain and the part of vehicle structure from mounts to tactile response location. In this paper, the contribution of rigid body motion of powertrain of a front wheel drive vehicle during key on/off is analyzed in both frequency and time domain. The signal is analyzed in frequency domain by using fast fourier transform, short time fourier transform and wavelet analysis. The merits and demerits of each method are
Rao, Manchi Venkateswara, Moorthy, S Nataraja, Raghavendran, Prasath
Driveline Torsional Analysis and Parametric Optimization for Reducing Driveline Rattle2015-01-217606/15/2015
Gear rattle is an annoying noise phenomena of the automotive transmission, which is mainly induced by torsional fluctuation of engine. In this study, torsional vibration of 3 cylinder powertrain is analyzed and improved for reducing the gear rattle from transmission by using parametric optimization. One dimensional Multi-body mathematical model for the torsional vibrations of front wheel drive automotive drivetrain is developed and utilized for the optimization of sensitive parameters of the driveline. Second order differential equations of the mathematical model are solved by using MATLAB and the output response is validated with the test data. Parametric optimization is conducted by using design of experiment method. The updated model is further utilized for optimizing the flywheel inertia, driveshaft stiffness and clutch stiffness. Mathematical modelling and optimization process has helped to achieve NVH targets for driveline.
Bhagate, Rajkumar, Badkas, Ajinkya, Mohan, Kiran
MMLV: Automatic Transmission Lightweighting2015-01-124004/14/2015
This paper details the lightweighting efforts of the Ford Research & Advanced Transmission team as part of the Multi Material Lightweight Vehicle Project. The Multi Material Lightweight Vehicle (MMLV) developed by Magna International and Ford Motor Company is a result of a US Department of Energy project DE-EE0005574. The project demonstrates the lightweighting potential of a five passenger sedan, while maintaining vehicle performance and occupant safety. Prototype vehicles were manufactured and limited full vehicle testing was conducted. The Mach-I vehicle design, comprised of commercially available materials and production processes, achieved a 364kg (23.5%) full vehicle mass reduction, enabling the application of a 1.0-liter three cylinder engine resulting in a significant environmental benefits and fuel consumption reduction. Several Ford 6-speed Front Wheel Drive (FWD) automatic transmission components were considered for lightweighting action with three ultimately being chosen as
Kearns, James, Park, Soon, Sabo, John, Milacic, Dusan
Study on Stability Control of Electrical Vehicle Based on Regenerative Braking System2015-01-156504/14/2015
A regenerative braking system coordinated controller was developed for a front wheel drive BEV that also includes an ultra-capacitor storage system. This controller integrates the dual-motor regenerative braking with the hydraulic braking and stability control systems. The vehicle braking mode and the distribution of braking torque were determined according to the vehicle braking requirements, vehicle status and energy storage system (battery plus ultra-capacitor) state, and the stability control torque was provided according to the real-time vehicle stability condition. Simulation results show that, compared with a motor unilateral independence control strategy, the integrated coordinated controller improves the vehicle's stability when the vehicle corners while braking.
Chen, Qingzhang
CAE-Based Driving Comfort Optimization of Passenger Cars2015-01-158304/14/2015
One of the key challenges in developing a vehicle for excellent vehicle dynamics is being able to achieve a high level of driving comfort without degrading the steering and handling performance. The part of driving comfort discussed in this paper are tactile vibrations up to f = 100 Hz. This paper describes how Multi-Body Dynamics (MBD) Computer Aided Engineering (CAE) tools are applied to optimize such vibrations in the early phase of the development process. The approach hereby presented combines system level testing with MBD for the study of ride comfort, similar to the way that system level kinematics and compliance testing is combined with MBD to support steering and handling investigations. Laboratory investigations have been executed to fully characterize a reference suspension with respect to frequency and amplitude behavior. The respective MBD models have been subsequently refined and validated versus physical laboratory measurements. Several examples for a front wheel drive
Drotar, Timothy, Palandri, Jacopo, Wolf-Monheim, Friedrich, Zandbergen, Paul, Reff, Bjoern
General Motors Front Wheel Drive Seven Speed Dry Dual Clutch Automatic Transmission2015-01-109304/14/2015
General Motors has introduced a new front wheel drive seven speed dry dual clutch automatic transmission in 2014. The 250 Nm input torque rated gear box was designed and engineered for a global market in both front wheel drive and all-wheel drive configurations. The transmission has integrated start/stop capability enabled by the use of an electric motor driven pump and a pressurized accumulator. The architecture selected was chosen for optimization of packaging, fuel economy, mass, shift pleasability, and NVH. High mileage durability and world class drivability were the cornerstone deliverables during the engineering and design process Fuel efficiency is estimated to be 3% - 10% improvement over a conventional six speed automatic transmission. FWD variant wet mass of 78.1 kg was achieved through the rigorous engineering processes used to optimize the transmission system.
Clark, Kirby S., Singh, Tejinder, Buffa, Ronald P., Gayney, Jack M., Cousins, William L., Xie, Zhe, Moorman, Steven P., Wilson, Alexandria, Fannin, Michael P., Graham, Mark L., Preston, Christopher B., Solt, Michael B., Varda, David J., Gilmore, Mark R., Foulkes, Martin G., Risko, Rebecca K.
Transmission Dynamic Modeling and Parametric NVH Analysis2015-01-114704/14/2015
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
Li, Dongxu
Vibration Reduction in Motors for the SPORT HYBRID SH-AWD2015-01-120604/14/2015
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
Yazaki, Manabu
Fault Diagnosis of Rolling Bearing Based on Time Waveform Analysis2015-01-167104/14/2015
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
Gear Fault Diagnosis Based on Optimal Morlet Wavelet Filter and Autocorrelation Enhancement2015-01-021204/14/2015
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
Beyond Driveline Disconnect - The Ultimate On-Demand Dry Sump RDM System with PTU Disconnect2015-01-109904/14/2015
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.
Creation of Halfshaft Joint Selection Tool in Terms of Strength and Life Calculations for FWD Vehicles2014-01-232909/30/2014
This study is inspired by the calculations and validations required for front wheel drive (FWD)-halfshaft joint selection. To increase design efficiency with decreased response time; a tool is required to validate calculations of strength based on maximum impact torque and endurance life based on corresponding vehicle usage. The tool has been developed to cover both strength and endurance life calculations. It also includes a constant velocity joint (CVJ) size library in order to compare different cases and to be able to see opportunities between different sizes. Validation and correlation has been completed using road load data from actual vehicles and standard load cycle (SLC) rig test results. This study introduces a more efficient methodology that will help the user select a joint that is sized best for strength and cost. After the completion of the study, one can be assured that the joint selected is the proper size-for all kinds of FWD vehicles.
Kaya, Sibel, Ayber, Barış
Electric Drive System for SPORT HYBRID SH-AWD2014-01-182104/01/2014
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
Ono, Koichi
Development of High Torque Capacity Variator System for CVT2014-01-172904/01/2014
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
Analysis of Drive Line Vibration and Boom Noise in an All Wheel Drive Utility Vehicle2014-01-197504/01/2014
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 Pathfinder2014-01-178804/01/2014
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
All-Wheel Drive Systems ClassificationJ1952_201310 (Historical)10/29/2013
In this SAE Recommended Practice, attention will be given to passenger cars and light trucks (through Class III).
Drivetrain Standards Committee
Automated Optimizing Calibration of Engine Driveability on the Dynamic Powertrain Test Bed2013-01-258810/14/2013
Engine calibration on the powertrain test bed with transient mode is proposed with dynamic powertrain test bed having low inertia dynamometer. Automated ECU (Engine Control Unit) calibration system is completed with the combination of experimental design software, powertrain test bed, evaluation tools and their electrical interfaces. The process is composed up of the system interface definition, test design using DoE skill, test proceedings by step sequence of connecting systems, measured data collecting, mathematical model and optimization result extraction at the end. All the processes are automated by interfaces between the systems. Acceleration surge is minimized by proposed process by optimizing combustion control labels and tip in driveability is maximized by manipulating torque filter labels of EMS (Engine Management System) logic. Their detailed steps from the problem definition to the verification test results of improved design with vehicle test are presented. The validation
Yoo, Jaegon, Lee, Heungseok, Jang, JungWoong, Hwang, Ohcheol, Chae, Chang-Kook
Simulation and Analysis Drive Transmission DevelopmentTBMG-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.).
The Development of FR-Based 4WD Multi-Link Suspension2013-01-123504/08/2013
In this paper FR (Front Engine, Rear wheel Drive) based 4WD 5-link independent suspension systems are introduced which are developed for low friction road stability in the winter. The arrangement of the lower control arm of the newly developed suspensions has been changed in order to correspond to 4WD layout. And basic performance is satisfied due to the addition of the driveline. Also NVH (Noise, Vibration and Harshness) performance has improved, to enhance the comfort of the vehicle
Jung, DaeWoo, Lee, Jae Kil, Lee, Byung-Kyu, Kim, Seon Pyung
Using Vehicle Simulation to Investigate Controllability2013-01-018004/08/2013
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
Ellims, Michael, Monkhouse, Helen Elizabeth, Harty, Damian, Gade, Teena
Parallel-Through-The-Road Plug-In Hybrid Vehicle Modeling and Simulation by Wayne State University for EcoCAR22013-01-054104/08/2013
The Wayne State University (WSU) EcoCAR2 student team designed, modeled, Model-In-the-Loop (MIL) tested, Software-In-the-Loop (SIL) simulation tested, and Hardware-In-the-Loop (HIL) simulation tested the team's conversion design for taking a 2013 Chevrolet Malibu and converting it into a Parallel-Through-The-Road (PTTR) plug-in hybrid. The 2013 Malibu is a conventional Front Wheel Drive (FWD) vehicle and the team's conversion design keeps the conventional FWD and adds a Rear Wheel Drive (RWD) powertrain consisting of an electric motor, a single speed reduction gearbox and a differential to drive the rear wheels -where none of these previously existed on the rear wheels. The RWD addition creates the PTTR hybrid powertrain architecture of two driven axles where the mechanical torque path connection between the two powertrains is through the road, rather than a mechanical torque path through gears, chains, or shafts. Finally, a battery pack and an on-board charger are added to complete
Snyder, Kevin L., Lor, Love, Ku, Jerry
Forward-Looking Simulation of the GM Front-Wheel Drive Two-Mode Power-Split HEV Using a Dynamic Programming-Informed Equivalent Cost Minimization Strategy2013-01-081504/08/2013
This paper presents a forward-looking simulation (FLS) approach for the front wheel drive (FWD) General Motors Allison Hybrid System II (GM AHS-II). The supervisory control approach is based on a dynamic programming-informed Equivalent Cost Minimization Strategy (ECMS). The controller development uses backward-looking simulations (BLS), which execute quickly by neglecting component transients while assuming exact adherence to a specified drive cycle. Since ECMS sometimes prescribes control strategies with rapid component transients, its efficacy remains unknown until these transients are modeled. This is addressed by porting the ECMS controller to a forward-looking simulation where component transients are modeled in high fidelity. Techniques of implementing the ECMS controller and commanding the various power plants in the GM AHS-II for FLS are discussed. It is shown that FLS-derived component states agree well with states commanded using the BLS-derived robust control strategy, with
Pei, Dekun, Leamy, Michael
New Launch Devices for Automatic Transmissions2013-01-023304/08/2013
Hydrodynamic launch elements, from the Foettinger principle of the torque converter to the first series production HCC wet clutch, are becoming more relied on in the transmission world for their high power density, launch comfort, and vibrational isolation capability. In order to attain the ambitious fuel economy objectives of the future, engine vibrations have to be successfully isolated from the driveline at low engine speed ranges without the use of the hydrodynamic circuit. This is now all the more challenging as new combustion engines are producing higher torsional vibrations as a result of fewer cylinders, higher combustion pressures, cylinder deactivation, and lower critical speeds. This paper will describe the next generation of powertrain vibrational isolation, dampening via powersplit. Additionally, a next generation wet launch element, the Hydrodynamically Cooled Clutch will be discussed. A brief description of the current state of the art dampening technologies will be
Binder, Scott William, Fischer, Matthias, Sasse, Christoph, Trampler, Joerg
Development of a Standard Spin Loss Test Procedure for FWD-Based Power Transfer Units2013-01-036104/08/2013
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
7-XDCT: Compact and Cost-Efficient Dual Clutch Transmission for Small and Mid-Size Vehicles2013-01-127104/08/2013
The automotive industry continues to develop new powertrain technologies aimed at reducing overall vehicle level fuel consumption. The ongoing trends of “downsizing” and “down speeding” have led to the development of turbocharged engines with low displacement and high torque density. In order to meet the launch response requirements with these engines as well as fuel economy needs, transmissions with large ratio spreads will need to be developed. Due to the lack of torque amplification from the torque converter, the next generation of dual clutch transmissions (DCT) will need to have larger launch ratios and ratio spreads than currently available in production today. This paper discusses the development of a new family of DCT (called “xDCT”) for use in front wheel drive vehicles, aimed at meeting some of these challenges. The xDCT family features two innovative concepts, the idea of “gear generation” and “supported shifts”. A combination of these features results in the development of
Govindswamy, Kiran, Hellenbroich, Gereon, Ruschhaupt, Johannes
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