Browse Topic: Drivetrains

Items (1,168)

Adaptive Speed Gearbox Design for the UH-60A Helicopter with integrated Electric Variator and Frequency investigation

F-0081-2025-0346

5/20/2025

This study presents the design, modeling, and simulation of an Adaptive Speed Gearbox (ASG) with integrated electric variator for the UH-60A Black Hawk helicopter. The proposed drivetrain architecture enables main rotor speed variation independently of turbine speed, addressing operational demands for enhanced efficiency, noise reduction, and performance flexibility. A comprehensive aero-thermal model of the turboshaft engine, a dynamic drivetrain model, and a variable-speed control strategy were developed and validated. The control approach employs a two-degree-of-freedom structure combining nullspace-based feedforward torque allocation and modal-weighted LQR feedback for vibration suppression. A similarity theory-based scaling method was employed to design a demonstrator gearbox, facilitating experimental validation under representative conditions. The results demonstrate the feasibility of the ASG concept and establish a foundation for future experimental investigations and subsequent technology maturation towards higher TRLs.

Scheu, Thomas, Weigand, Michael, Gross, Christopher, Poks, Agnes, Willinger, Reinhard

Optimization of Electrified, Variable Speed Drivetrain Concepts for Enhanced Vehicle Performance

F-0080-2024-1315

5/7/2024

Hybrid-electric propulsion could provide numerous benefits for full-size rotorcraft, including reduced peak turbine power demand, reduced transmission system weight and complexity, and reduced operating costs. Variable speed electric motors, furthermore, could be configured to enable continuously variable rotor speed. Achieving these benefits requires accounting for coupling between the hybrid-electric drivetrain and vehicle performance within a large, unexplored design space. This paper presents a framework for simultaneous optimization of vehicle and electrified powertrain conceptual design using Geometric Programming (GP) methods. Four hybrid-electric powertrain architectures are evaluated relative to a baseline non-electrified powertrain for single main rotor, compound coaxial-rotor, and tiltrotor configurations. For designs with an upper limit on turbine power, electrification increases the maximum cruise speed for the compound coaxial-rotor configuration. Variation of the rotor speed by 15% allows the vehicle to carry 8% more fuel, relative to the non-electrified baseline, and 1,246 lb of battery. Operating the rotor at optimal speeds across the mission results in increased off-design mission performance, most notably a 43% increase in transport radius relative to a baseline powertrain. The results demonstrate the utility of the design optimization framework for exploration of novel hybrid-electric concepts as well as the challenges associated with incorporating electrical components into the drivetrain.

VanLandingham, Aaron, Bill, Robert, Smith, Edward, Hall, David

Dynamic Behaviour of a Rotorcraft Main Rotor System with Variable Speed

F-0080-2024-1368

5/7/2024

Current Rotorcraft Developments like under the Future Vertical Lift Program in the USA (e.g. Bell V-280, see figure 1) respectively RACER (Airbus Helicopters, see figure 2) and NextGENCivil Tiltrotor (Leonardo, see figure 3) in Europe deal with High-Speed Rotorcraft or Tiltrotor-/Tiltwing Aircraft. They can expand and optimize their performance by using a variable rotor speed either to adopt the rotor speed to high forward speed or to meet the different requirements of a rotor in Hover and Aircraft Mode of a Tiltrotor-/Tiltwing Aircraft. As the required speed range can not be covered by the turbine, TU Munich (Germany), TU Wien (Vienna, Austria), ADT - Advanced Drivetrain Technologies (Austria) and Zoerkler Gears (Austria) work in the transnational project "VARI-SPEED II" on a rotor system that can change the rotor speed via change of the ratio of the transmission (variable rotor speed with constant turbine speed). The project is based on the results of "VARI-SPEED" and the direct follow-up project. VARI-SPEED showed that a rotor speed variation performed by a transmission system is possible. The efficiency and the flight envelope of the rotorcraft can be improved by this technology. Furthermore, a method for rotor blade design in a RPM range was invented. VARI-SPEED II now has built up a model of the complete dynamic system from engine to rotor of a helicopter with a variable speed rotor. This model is used for dynamic simulations of the components and the whole system. A scaled model of the module that changes the speed will be developed and pilot studies in a simulator are planned to find out the characteristics of such a system. Aim of the project is to reach TRL 3 as basis for further development of the technology with interested OEM's. This paper deals with the dynamic behaviour of the components and the whole drive train. The Bell V-280 is in the flight testing phase, RACER has recently conducted its maiden sortie and for the NextGENCtr the first flight is announced for the first half of 2024. All mentioned aircraft use transmission systems with a fixed gearbox ratio; this is feasible as a new technology like Vari-Speed normally is not added to completely new rotorcraft. However as the OEM's rate Vari-Speed positive, variable rotor speed can be integrated in a later development stage of the rotorcraft and thus development timelines of the rotorcrafts and Vari-Speed match quite well.

Scheu, Thomas, Koch, Jonas, Poks, Agnes, Weigand, Michael

Prediction of Structural Rotor Loads: When to Consider Drivetrain Dynamics?

F-0080-2024-1209

5/7/2024

The constant, undisturbed rotor hub rotational speed is a commonly applied boundary condition and simplification in computational analyses of helicopter rotors. Revoking this simplification and considering rotor-drivetrain interactions in the hub's rotational degree of freedom can - but doesn't necessarily - improve the predictions of structural blade loads, especially in the lead-lag direction. To estimate the drivetrain's potential to influence the lead-lag loads, this paper proposes the systematic evaluation of the modified collective lead-lag modes. These eigenmodes, as well as the resulting modification of lead-lag loads in the aeromechanic simulation, are presented and compared for the rotordrivetrain configurations of the Eurocopter Bo105 and the Sikorsky UH-60A. The study focuses on understanding the drivetrain's influence rather than on making high fidelity predictions. In the Bo105 case, the drivetrain impact on the lead-lag moments is significantly more pronounced than for the UH-60A. The discussion of this difference includes the assessment of the blade passage frequency magnitudes (4/rev for a number of nb = 4 rotor blades) and their sensitivity to the modified collective second lead-lag eigenfrequency, which in turn is changed by a varying drivetrain stiffness. While a very stiff drivetrain causes an eigenfrequency of 4/rev with high-magnitude resonance for the Bo105, the UH-60A configuration maintains an eigenfrequency above 4/rev for the whole range of applied stiffness values. For rotor-drivetrain systems, especially near resonance, the nb/rev magnitudes of the lead-lag loads are very sensitive to changes in the drivetrain properties as well as changes in the nb/rev excitations. The accurate modeling of these nb/rev excitations, e. g. by airloads, is essential to capture changes in the nb/rev dynamic response that are caused by the drivetrain. Therefore, including the drivetrain in the structural model may only be useful if the fidelity of other models is increased simultaneously.

Weiss, Felix

High-Speed Compound Rotorcraft Performance and Design

F-0080-2024-1150

5/7/2024

High-speed configurations are among the new emerging concepts that are currently expanding the scope of rotorcraft design. Especially in the field of defense technology research, the capability of a substantial increase in maximum velocity becomes more interesting. For instance, NATO project NGRC is considering this capability for a new medium utility rotorcraft. DLR supports these activities by its continuing defense technology research. In this study the benefits and drawbacks of a high-speed capability for a given mission scenario are analyzed. For that purpose, a contemporary configuration has been modeled, featuring a maximum velocity of 82 m/s (160 KTAS). The high-speed configuration meets with the same mission requirements, but with an increase of about 50% of maximum speed to 125 m/s (242 KTAS). All tasks in this study are conducted with DLRs integrated design environment IRIS. The high-speed configuration features an off-loaded main rotor, a wing, a propeller and a reduction of the rotational speed of the drive train for the extended flight envelope. The reference configuration as well as the high-speed rotorcraft were compared with the focus on flight performance.

Weiand, Peter, Schwinn, Dominik, Atci, Kagan

Steering Control Systems - Heavy Trucks

J2425_202111 (Current)

11/9/2021

This SAE Recommended Practice describes a laboratory test procedure and requirements for evaluating the characteristics of heavy-truck steering control systems under simulated driver impact conditions, as well as driver entry/egress conditions. The test procedure employs a torso-shaped body block that is impacted against the steering wheel.

Truck Crashworthiness Committee

Application Guide for Aerospace Hydraulic Motors

ARP4940A (Current)

11/9/2021

This SAE Aerospace Recommended Practice (ARP) is an application guide for fixed and variable displacement hydraulic motors. It provides details of the characteristics of fixed and variable displacement hydraulic motors, architectures, circuit designs, controls, and typical applications. The applications include airborne and defense vehicles with emphasis on high performance applications.

A-6C4 Power Sources Committee

Mission Performance and Cost Calculation for variable Rotor Speed Drivetrain

F-0077-2021-16885

5/10/2021

ABSTRACT

Amri, Hanns, Auer, Andreas, Gross, Christpoher

AW609 Civil Tiltrotor Drive Train Torsional Stability Analysis and Certification Test Campaign

F-0077-2021-16772

5/10/2021

ABSTRACT

Haidar, Ahmad, Belluomini, Luca, Trezzini, Alberto

Universal Joint End Yoke Connection (Earwork)

J2301_202101 (Current)

1/7/2021

This document specified the main dimensions and tolerances which affect interchangeability between end yoke earwork for the most common North American-used universal joints. Dimensions and tolerances of the mating universal joints are left to the discretion of the universal joint manufacturers. The term “earwork” refers to the configuration and geometry defining end yoke connections directly provided for universal joint cross attachment of drivelines. Earwork for certain styles of universal joint connections and flange connections have for a long time been proprietary to certain manufacturers. Over years of usage, proprietary rights have expired and the industry, as a whole, has used these earworks as standard. In an effort to tabulate some of the long-established practices, the following SAE Recommended Practice has been compiled. Manufacturers do from time to time, as the need arises, change tolerances or fits to better enhance component performance. This document has been prepared as a reference, and is a snapshot of current technology. The half round (strap connection), full round (retainer plate type connection), and wing type connection are covered in this document. For an understanding of these end yoke styles, please refer to SAE J901. There are earwork forms that still are proprietary and are not covered by this document.

Drivetrain Standards Committee

Static Transmission Error Analysis of a Hybrid Spur Gear Drivetrain

F-0076-2020-16334

10/5/2020

This study presents static analyses of transmission error in a single gear pair gearbox for six pairs of hybrid composite-steel spur gear designs developed in a previously presented optimization effort. The results were compared to those of the same gearbox featuring a baseline all-steel gear pair. The gearbox models were developed in the commercial software RomaxDESIGNER R17. A tooth stiffness analysis was also conducted to replace the tooth stiffness values calculated in Romax with values that consider the web effects on tooth stiffness. These stiffnesses are used to calculate the mesh stiffness. This analysis showed a 2-5% difference in average tooth stiffness of the hybrid gears compared to the steel gear. The transmission error analysis with the new tooth stiffnesses showed a 1-3% increase in the transverse error in for hybrid gears compared to the baseline steel.

Gauntt, Sean, Campbell, Robert, McIntyre, Sean

Directional Vehicle Control by Steering the Third Axle to Provide Redundancy for Steer-by-Wire Systems and Highly Autonomous Vehicles

02-13-03-0015

9/25/2020

A way of providing steering redundancy for highly autonomous vehicles or vehicles equipped with steer-by-wire systems by steering the rear axle for directional control of the vehicle has been previously proposed. In this study, we further investigate and improve on that concept and validate it through simulation and experimental testing on a vehicle. Consequently, we show that in the case of failure of primary front axle steering system, the vehicle controller steering command (in the case of autonomous driving) or the driver’s steering command (in the case of a steer-by-wire system) can be mathematically manipulated to generate a steering input at the rear axle, which results in the same yaw rate response as if the vehicle was steered from the front, and thus providing a way to control the vehicle should a failure occur in the primary steering system.

Nhila, Amine, Williams, Dan E.

Modeling and Analysis of a Heavy Vehicle with Self-Steering Axle

02-13-01-0003

4/21/2020

Commercial vehicles often incorporate self-steering axles to meet the axle load requirements while providing improved maneuverability, reduced off-tracking, and reduced tire and pavement wear. Market forces promote the design of more efficient self-steering axle products with reduced weight and more features. Manufacturers also work to differentiate their products through unique designs and new concepts. Traditional design methods for self-steering axles include empirical and trial-and-error methods to set the steering mechanism design parameters based on known design baselines and prior experience. For innovative new concepts that are too far from the traditional designs, it is desirable to have alternative ways for evaluating the expected performance. This article introduces a reduced-order model that allows the rapid analysis of the steering dynamic behavior of self-steering axles. The model combines a pendulum-like lateral stiffness model with the axle steering dynamics which are then coupled to suitable reduced-order models for tractor-trailer combinations on which the self-steering axle can be mounted. The proposed model is shown to capture the shimmy behavior of the self-steering axle using phase portraits of the coupled nonlinear system. The model provides a way to identify the important stiffness and damping parameters of steering axle design concepts that are not yet sufficiently developed, and therefore the details required for full multi-body dynamic analysis are not available.

Delorenzis, Damon, Ayalew, Beshah

Development of New Hybrid Transaxle for Mid-Size Sports Utility Vehicles

2020-01-08504/14/2020

Toyota has developed a new Hybrid (HV) transaxle P810 for Mid-Size SUVs to improve fuel efficiency and power performance. The transaxle was developed based on Toyota's new development strategy - Toyota New Global Architecture (TNGA). By adopting technologies to shorten overall length of the transaxle, installation into the same engine compartment of Mid-Size sedans have been realized while also improving the motor output. This paper will introduce technologies regarding the new mount structure for shortening overall length, and furthermore, noise reduction related to this mount structure.

Nobuyasu, Seitaro, Iwata, Shigetsugu, Nishigaya, Masabumi, Hagino, Yoshiteru, Ito, Masatoshi, Aihara, Hiroshi

Research on Tracking Algorithm for Forward Target-Vehicle Using Millimeter-Wave Radar

2020-01-07024/14/2020

In order to solve such problems that the millimeter-wave radar is of large computation, poor robustness and low precision of the target tracking algorithm, this paper presents an algorithmic framework for millimeter-wave radar tracking of target-vehicles. The target measurement information outside the millimeter- wave radar detection range is eliminated by the data plausibility judgment method based on the millimeter-wave radar detection parameters. Target clustering is made using Manhattan distance, to eliminate clutter interference and cluster multiple target measurements into one. The data association is made by use of nearest neighbor to determine the correspondence between information received measured by the radar and the real target. The vehicle is the key detection target of the vehicle millimeter-wave radar during road driving. These target-vehicles generally have no vertical movement or small moving speed in the vertical direction, so only the movement of the target-vehicle in the XY plane needs to be considered. Since the target-vehicle motion state has the characteristics of small mobility, a constant acceleration model is established based on the millimeter-wave radar motion coordinate system to describe the motion state of the front target-vehicle. The motion state are tracked and optimized by the algorithm of improved adaptive extended Kalman filter (IAEKF), because it is difficult to determine the statistical property of its measurement noise. A differential position system is formed by installing a base station on the ground and RT3000s on the ego-vehicle and target-vehicle, respectively. Differential Position System is formed by installing Base Station on the ground and high-precision inertial navigator RT3000s and RT-XLANs on the ego-vehicle and target-vehicle, respectively. By use of the differential position system, with effective communication, the relative distance and speed information between both vehicles can be obtained in real time to verify the accuracy of the millimeter-wave radar target tracking algorithm. Results show the proposed algorithm is feasible and of high estimation accuracy.

Song, Shiping, Wu, Jian, Yang, Yu, He, Rui, Chen, Xuesong, Li, Xin

Evaluation of Methods for Identification of Driving Styles and Simulation-Based Analysis of their Influence on Energy Consumption on the Example of a Hybrid Drive Train

2020-01-04434/14/2020

Due to current progresses in the field of driver assistance systems and the continuously growing electrification of vehicle drive trains, the evaluation of driver behavior has become an important part in the development process of modern cars. Findings from driver analyses are used for the creation of individual profiles, which can be permanently adapted due to ongoing data processing. A benefit of data-based dynamic control systems lies in the possibility to individually configure the vehicle behavior for a specific driver, which can contribute to increasing customer acceptance and satisfaction. In this way, an optimization of the control behavior between driver and vehicle and the resulting mutual system learning and -adjustment hold great potential for improvements in driving behavior, safety and energy consumption. The submitted paper deals with the analysis of different methods and measurement systems for the identification and classification of driver profiles as well as with their potential to optimize both vehicle driving behavior and energy consumption on the example of a hybrid drive train. A literature research results in a number of different approaches of evaluation, which are analyzed, linked and adapted in the publication. As a result, an evaluation of the connection between different methods of driver profile determination is given. Data collection and interviews have been performed during twenty test drives on a defined route profile with different measurement systems and methods. The acquired data form the basis for a comparison and an analysis of a comprehensive driving style classification. Subsequently, a framework for computer-aided investigations of the influences of driver behavior on the control of drive trains is established by use of an existed simulation model of a hybrid drive train. Finally, a driver model is implemented based on the learnings out of analyzing the measurements and surveys. The evaluation of the measurement campaigns delivers detailed information about vehicle longitudinal acceleration behavior in different driving scenarios. This information is used to classify the individual driving styles into the types calm, normal and aggressive. This driving style-related information can be integrated into the control strategy of a hybrid power train to support operation strategy optimization regarding both driver satisfaction and reduction of energy-, respectively fuel consumption.

Domijanic, Marko, Hirz, Mario, Pucher, Gregor

Research on Control Strategy Optimization for Shifting Process of Pure Electric Vehicle Based on Multi-Objective Genetic Algorithm

2020-01-09714/14/2020

With more and more countries proposing timetables for stopping selling of fuel vehicles, China has also issued a “dual-slope” policy. As electric vehicles are the most promising new energy vehicle, which is worth researching. The integration and control of the motor and gearbox have gradually become a hot research topic due to low cost with better performance. This paper takes an electric vehicle equipped with permanent magnet synchronous motor and two-gear automatic transmission without synchronizer and clutch as the research object. Through the action of the motor, gearbox and shift actuator in the shifting process, the whole vehicle dynamics is modeled in each stage of shifting, a method for determining a short-term driving style intensity factor for decision shifting is proposed, three evaluation indexes of the shift quality of electric vehicle are put forward, the control parameters affecting the shift quality are analyzed, and the mathematical relationship between the shift control parameters, the shifting time and the shifting impact are obtain. Besides, the NSGA-II algorithm is used to carry out multi-objective global optimization of the whole process of shifting to get Pareto optimal solution. Analyze the optimization results in combination with driving style, determine some thresholds and parameters of the drive motor and shift actuator action control during the shifting process, improve the shift control strategy, and finally complete the coordinated control of the shifting process of the electric drive system based on the active synchronization of the motor. The results show that the optimization effect is good. It provides a new idea for the shifting process control of the pure electric vehicles.

Lei, Yulong, Zhang, Jingxu, Fu, Yao, Jia, Fuchun, Wang, Binyu

An Interval Analysis and Optimization Method for Generated Axial Force of Automotive Drive Shaft Systems

2020-01-09184/14/2020

To study the generated axial force (GAF) of the drive shaft system more accurately and effectively, this paper introduces the interval uncertainty into the research focusing on the GAF. Firstly, an interval uncertainty model for calculating the GAF is proposed based on the Chebyshev polynomials and an analytical model of the GAF. The input torque, the articulation angle, the rotation angle of the drive shaft system, the pitch circle radius (PCR) of the tripod joint and the friction coefficient are regarded as interval variables. Secondly, the upper and lower bounds of the proposed GAF model under interval uncertainty parameters are calculated quickly with the vertex method. Then the interval uncertainty optimization of the GAF under uncertainty parameters is performed. The upper bound of the response interval of the GAF is taken as the optimization object. Finally, the proposed model is verified by experiments, while the interval uncertainty analysis and optimization of the GAF are carried out through a numerical example.

Feng, Huayuan, Rakheja, Subhash

Research on Fractal Friction Model between Balls and Arc Raceways inside a Ball Joint

2020-01-10934/14/2020

During the operation of the ball joint, its service life and transmission efficiency are affected by the internal friction. Taking the ball joint as the research object, based on fractal theory, the friction between the steel ball and the raceway inside the ball joint of an automotive drive shaft system is studied in this paper. During the analysis, the friction between the steel ball and the arc raceway is regarded as the friction between a sphere and an arc raceway surface. In order to describe the friction state more accurately, this paper proposes a correction coefficient to modify the distribution function of contact asperities in the plane, and obtains the distribution function of contact asperities between the sphere and the arc raceway surface. The correction coefficient is related to the load, the size parameters and the material parameters of the steel ball and the raceway. Then based on the modified distribution function, the fractal models of the friction coefficient, the tangential force (the friction force) and the normal contact load between the steel ball and the raceway are established. Finally, the correction coefficient is verified by the finite element model, while the relationship between the correction coefficient and the load, the relationship between the friction force and the normal contact load, and the relationship between friction coefficient and fractal parameters are analyzed through numerical examples.

Feng, Huayuan, Li, XiHua

Bollinger Motors showcases second-gen Class-3 EV prototypes

19AUTP11_1611/1/2019

Bollinger Motors recently unveiled its second-generation Class-3 EV prototypes. The start-up, based in Ferndale, Michigan, revealed the latest beta of its B1 SUV and B2 truck prototypes, highlighting the amount of in-house engineering and design. As a Class 3 (GVWR 10,001 to 14,000 lb.) vehicle, the Bollinger Motors truck and SUV are in the same classification as a Ford F-350 or Ram/Chevy 3500 truck. “This is the only all-electric Class 3 truck with off-road capability,” founder and CEO Robert Bollinger said of the B2. “Our beta version vehicles look very much like the original alpha prototype vehicle that debuted in 2017, but almost every component on our B1 SUV and B2 truck prototypes is different,” said Karl Hacken, Bollinger Motors chief engineer. The four-door B1 and B2 are identical from the C-pillar forward, with the B2 truck's 139-in wheelbase stretching 20 inches longer than the SUV. Both aluminum-bodied prototypes feature a vehicle-length 16×14-in pass-through enabled by packaging the driveline systems below the floor.

Buchholz, Kami

Towed Vehicle Drivetrain Test Procedure Passenger Cars, Vans, and Light-Duty Trucks

J1144_201910 (Current)10/28/2019

Motor Vehicle Council

Setting Preload in Heavy-Duty Wheel Bearings

J2535_201910 (Current)10/7/2019

Truck and Bus Wheel Committee

GKN spreads premium propshaft tech to quiet pickup cabins

19AUTP10_1110/1/2019

It may seem a long way in engineering and NVH terms from premium European cars such as Audi's A5 and A7 to light duty trucks, but GKN Automotive has bridged that gap with its latest lightweight all-wheel drive (AWD) modular propshaft. Many pickups suffer a significant amount of unwanted NVH emanating from the front propshaft, with its two universal or CV joints and an interconnecting shaft positioned below and close to the passenger cabin. But now GKN Automotive has “re-characterized” its premium car driveline system to an entirely different vehicle category. “With a traditional truck front propshaft, the level of noise entering the cabin is perceived as a drone,” explained Michael Miller, GKN's propshaft product technology manager. “We've worked on applications of our new technology where the cabin NVH levels have been dramatically reduced. Positive results stem from the combination of joints used in our lightweight modular front propshaft.”

Birch, Stuart

The Improvement Brake’s Qualities of Vehicle by Developing the Method of the Choosing Frictional Pairs of the Brakes Mechanisms

2019-01-21459/15/2019

One of the reasons for the large number of road accidents on highways in Ukraine [1] is the instability of the braking properties due to the unstable characteristics of the brake mechanisms’ friction pairs. The manufacturer produces new automobiles with installed brake pairs (brake pads and their counter bodies), which have passed long-term tests for the stability of the friction coefficient and braking forces distribution of between the axles. This ensures the compatibility of the friction pairs characteristics for front and rear brake mechanisms according to the criteria of heat resistance. During operation, instead of worn-out brake pads, brake discs and drums, drivers can purchase new ones, manufactured as spare parts. However, in the well-known literature there are no methods that allow to check the compatibility of the friction pairs characteristics for front and rear brake mechanisms according to the criteria of heat resistance. In the article a method for choosing a set of friction pairs of brake mechanisms for passenger car during operation is proposed. Assessment of the compatibility of the friction pairs characteristics for front and rear brake mechanisms was carried out according to the criteria of heat resistance.

Podrigalo, Mikhail, Klets, Dmytro, Kholodov, Mykhailo, Bogomolov, Viktor, Turenko, Anatoliy, Molodan, Andrii, Rudzinskyi, Volodymyr, Tarasov, Yurii, Mykolai, Aloksa, Hatsko, Vasyl

Stability of Wheel Tractors during Braking

2019-01-21429/15/2019

The dynamic distribution of normal reactions between the axles of the wheeled tractor has a significant impact on the stability against skidding and the wheeled tractor braking effectiveness. At the same time, the clarification of the normal reactions distribution between the axles allows to choose more rational braking forces distribution between the axles. It is shown that the best way to ensure the highest braking efficiency is the braking mode when the rear wheels of the tractor are at the blocking limit. An assessment of the expediency of installing brake mechanisms on only one axle of the tractor was made. The increase of braking efficiency of wheeled tractors with all brake wheels provided that they ensure directional stability is considered. The laws of braking forces distribution between the axles of wheel tractors for different sequence of wheels locking are determined. Using the method of partial accelerations an improved method for estimating the effect of a brake system on the stability of wheeled tractor is proposed. The criterion in the form of angular acceleration in the road plane ώz, by the value and sign of which one we can estimate the operational stability of the brake mechanisms has obtained.

Podrigalo, Mikhail, Kholodov, Mykhailo, Klets, Dmytro, Dubinin, Yevhen, Savchenkov, Borys, Koryak, Alexander, Rudzinskyi, Volodymyr, Viktoriia, Zadorozhnia, Polianskyi, Oleksandr

Analysis of the Tractor-Trailer Dynamics during Braking

2019-01-21449/15/2019

The intensive development of tractor-building industry in the world has led to the widespread use of wheeled tractors and tractor trains in transportations on public highways. This requires an increase of engine capacity and speed of tractor trains, as well as strict demands for their braking systems. The formation of the necessary braking properties of wheeled tractors and tractor trains on their basis should be carried out at the design phase, taking into account a wide range of aggregated machines and tools. Blocking the wheels of the trailer with different sequence of their blocking and blocking the wheels of the tractor has significant impact on the total braking force, deceleration and stability of the tractor train. It is advisable to take this into account when modeling the braking process of a tractor train. The article deals with the braking dynamics of the tractor train and the impact of the dynamic distribution of normal reactions between the axles on the brake properties of the tractor train. The mathematical model of the braking process of the tractor-trailer train (consisting of a wheeled tractor and a two-axle trailer at the limit of blocking the wheels) has been obtained. The coefficients of the total braking force distribution between the to the front and rear axles of the tractor, front and rear axles of the trailer, ensuring the directional stability of the tractor-trailer train, have been determined.

Podrigalo, Mikhail, Klets, Dmytro, Kholodov, Mykhailo, Klimenko, Valeriy, Rudzinskyi, Volodymyr, Kholodov, Anton

Modelling and Control of a Novel Clutchless Multiple-Speed Transmission for Electric Vehicles

2019-24-00639/9/2019

Conventional electric vehicles adopt either single-speed transmissions or direct drive architecture in order to reduce cost, losses and mass. However, the integration of optimized multiple-speed transmissions is considered as a feasible method to enhance EVs performances, (i.e. top speed, acceleration and grade climbing), improving powertrain efficiency, saving battery energy and reducing customer costs. Perfectly in line with these objectives, this paper presents a patented fully integrated electric traction system, as scalable solution for electrifying light duty passenger and commercial vehicles (1.5-4.2 tons), with a focus on minibuses (<20 seats). The adoption of high-speed motor coupled to multiple-speed transmission offers the possibility of a relevant efficiency improvement, a 50% volume reduction with respect to a traditional transmission, superior output torque and power density. The proposed clutchless four-speed transmission is specifically conceived and designed to have the good matching with the traction electric motor. Indeed, clutches and synchronizers are not required thanks to the small inertia of the traction motor and its fast regulation in both torque and speed mode (torque modulation process). Therefore, an advanced shifting control system/strategy has been developed to reduce the time shifting, linked to the degree of jerk and the power interruption, guaranteeing the coordination of all the gear-shifting actuators despite the randomness of the gear shifting process. After the description of the system layout, the paper gives an insight of the plant dynamic model and its equations. The controller architecture along with its strategies are also presented. The effectiveness of the proposed solution is proven through an extensive set of simulations carried out for a vehicle running on a real driving cycle.

Malafronte, Ludovica, Grandone, Mauro, Lega, Alberto, Pennese, Michele, Pianese, Cesare

THE LIMITATIONS OF THE UNIVERSAL JOINT

0800146/25/2019

VANDERBEEK, H.

Kinematic Analysis and Simulation of the Double Roller Tripod Joint

2019-01-15266/5/2019

The kinematic model of the double roller tripod joint is established in order to analyze its kinematic characteristics and provide theoretical basis for its application and improvement. By means of spatial coordinate transformation, the translational and rotational motion equations of the rollers relative to the tracks and trunnions, the motion equation of the center of the tripod and the equations of the input/output angular displacement error and bending angle are derived. The motion simulation of the double roller tripod universal joint was carried out in ADAMS so as to verify the established kinematic model. The results show that the rollers of the double roller tripod joint only have periodic translational motions relative to the tracks while the rollers have both periodic translational and rotational motions relative to the trunnions. The tripod’s center does the circular motion on the tripod plane with the angular velocity 3 times of the input angular velocity. The input/output angular displacement error and bending angle have volatility, and their fluctuating frequency are 3 times of the input rotational frequency. Hence, the double roller tripod joint is a quasi-constant-velocity joint whose rollers only do pure rolling motion in the tracks.

Qiu, Yinyuan, Shangguan, Wen-Bin

New Half Shaft Bench Test Methodology for NVH Characterization

2019-01-15586/5/2019

The main purpose of this paper is to develop a reliable bench test to understand the vibratory behavior of the half shafts under applied torque comparable to an idle condition. In some cases, the half shaft path is a major factor influencing the idle vibration in the vehicle. At idle condition vehicle vibrations are caused by engine excitation and then they pass through different paths to the body structure. Half shaft manufacturers generally characterize shaft joints for their frictional behavior and typically there is no data for vibration characteristics of the half shaft under idle conditions. However, for predictive risk management, the vibratory behavior of the half shaft needs to be identified. This can be achieved from measured frequency response functions under preloaded test conditions. This bench test enables manufacturers to conduct comprehensive design of experiments on the impact of powertrain vibration input while transmitting through the half shaft into the vehicle system. This method enables the study of the half shaft at the component level, because studying the half shaft at vehicle level is difficult since other paths are present. This paper describes the bench test methodology and presents certain boundary condition challenges of the half shaft measurements, the design of the test rig and the preliminary joint behavior results on the test bench.

Siavoshani, Saeed, Vesikar, Prasad Balkrishna, Yuan, Wei, Abbas, Ahmad, Sturla, Francisco Antonio

Improvement of Hypoid Gears Dynamics Performance Based on Tooth Contact Optimization

2019-01-15636/5/2019

The meshing noise of hypoid gear has a significant influence on driving axle system. It should be strictly controlled in order to reduce the whole vehicle noise. Meshing internal excitation of hypoid gear is a main source of vibration noise, closely connected with geometrical shape and meshing status. There is no comprehensive analysis on the impact of various contact patterns on vibration noise in previous studies. Therefore, the method for controlling contact characteristics of hypoid gears is studied in this paper, which includes adjusting the position and length of contact pattern, direction of contact trace and the theoretical transmission error. Also, a non-linear dynamic model with multi-freedom for the hypoid gear pair of the driving axle is established to evaluate the dynamic response of the gear pair. Then an example was carried out to improve the dynamic characteristic of hypoid gears by tooth profile modification. It is proved that the dynamic transmission error and mesh force can be reduced effectively through reasonably controlling the contact characteristic parameters of the gear pair. This complete process of tooth profile design, dynamic analysis and tooth contact characteristic adjustment is therefore demonstrated to be an effective approach to the optimization of hypoid gear design in order to acquire good vibration and noise performance of the driving axle.

Zhang, Weiqing, Wang, Yawen, Lin, Chia-Ching, Lim, Teik, Guo, Xiaodong, Wang, Kan, Zheng, Yong

Development of an Analytical Method for Rear Differential Gear Whine Noise Utilizing Principal Component Contribution by OTPA and CAE

2019-01-15556/5/2019

The progress of vehicle electrification has reduced engine noise and the improvement of rear differential gear whine noise has become more important for customer satisfaction. Rear differential gear whine noise is a result of the vibration generated by the transmission error of the gears transmitted to the cabin from various paths. As several components have a contribution, identifying key paths to develop an effective countermeasure becomes time consuming. Operational transfer path analysis (OTPA) is one of the TPA methods to determine the main path and contributing part using only the operational data. However, in cases where many reference points are set on the same frame or body, the contribution becomes similar because of high correlation between the reference data set. As a result, finding the main transfer path becomes difficult. To overcome this issue, the principal component (PC) contribution obtained from the correlated reference signals was established by modifying the OTPA process. Through this process, important vibration behavior of the target structure can be obtained as the high contributing PC mode. In this paper, this approach was applied to a vehicle and verified. In addition, for applying the method, enormous signals at the reference and response points are necessary to be recorded simultaneously. This issue makes the method difficult to be applied especially to the high frequency phenomenon. This issue was solved by using frequency responses calculated from finite element (FE) models which were converted to transient data by inverse fast Fourier transform (FFT). After obtaining sufficient amount of data by using simulation, the data was used to identify the high contributing PC modes and the vibration modes. Using these findings, the vehicle was retrofitted, the vibration and sound pressure levels were confirmed to decrease and the effectiveness of the developed method was verified.

Nakatsuka, Miho, Miwa, Tetsuya, Yoshida, Junji

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

2019-01-14556/5/2019

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

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

Design Optimization of a Hybrid Spur Gear

F-0075-2019-14674

5/13/2019

This study develops an optimization technique for a sinusoidal interlock design of a hybrid spur gear consisting of a metallic outer ring to support high contact stress bonded to a composite inner web for weight reduction. Two objectives (mass and shear traction on the metal-composite interface under static loading conditions) were minimized for four design variables subject to two constraints. Borg MOEA, a multi-objective evolutionary algorithm developed at The Pennsylvania State University, and an in-house finite element solver were used to generate Pareto-optimal solutions to this design problem. Two of the designs were then analyzed in greater detail to determine stress distributions throughout the gear. In the future, this technique will be refined and applied to optimization of more representative rotorcraft gears, with the aim of reducing drive train weight and meeting performance requirements.

Gauntt, Sean, Campbell, Robert, McIntyre, Sean

Experimental Investigation of Sliding on Tripod Constant Velocity Joints

2019-01-50173/13/2019

An automotive transverse transmission is articulated by mechanisms called constant velocity joints (CVJ). The joint allows the suspension to move freely. Its frictional behavior is not well known. However, the CVJ functional analysis makes it possible to identify important mechanical losses due to the friction of component elements. This article will focus on tripod side. An analysis of its behavior by designing and constructing a rig in order to qualify the sliding inside of the tulip between tracks and rollers has been initiated. Thanks to three-dimensional (3D) printing and sport camera a new approach was established.

Ripard, Valentin, Ville, Fabrice, Cavoret, Jérôme, Ruzek, Michal, Charles, Pierre, Diaby, Moussa

ABS Exciter Ring Location Standardization

J1730_201902 (Historical)2/11/2019

Truck and Bus Wheel Committee

Optimizing Steering Column Layout and UJ Phase Angle to Enhance Vehicle Dynamics Performance

2019-01-50102/5/2019

Vehicle dynamics is one of the most important vehicle attributes. It is classified into three domains, the longitudinal, vertical, and lateral dynamics. This paper focuses on optimizing the lateral vehicle dynamics which is driven by the straight ahead controllability and cornering controllability of the vehicle. One of the important parameters that dictates these sub-attributes is the steering ratio. Therefore, designing the right steering ratio is critical to meet the vehicle “specific” targets. Significant amount of work has been done by many researchers on variable steering ratio by implementing variable gear ratio (VGR) rack, active steering, and steer-by-wire systems. This paper discusses the methodology and considerations to optimize the steering ratio for a constant gear ratio rack by optimizing the steering column layout, viz., orientation and the phase angle in universal joints. A detailed analysis of steering system layout is done to optimize the steering ratio to enhance the vehicle dynamics performance. Full vehicle-level multibody dynamics (MBD) simulations are done in ADAMS® to compare the vehicle response behavior for different steering ratios in the open-loop objective tests. The Computer Aided Engineering (CAE) results show significant impact of the proposed design methodology on vehicle controllability. When the phase angle and the initial column angle are optimized for a quick on-center steering ratio, the response gains are higher, resulting in a sporty and agile feel. However, when the same vehicle is tuned for a slower on-center steering ratio, the gains are lower, resulting in a sluggish, lazy feel. This methodology can be implemented during the initial vehicle design phase to optimize vehicle performance.

Puvvula, Praneeth, Ravuri, Susheel, Dubal, Ajit, Salunkhe, Swapnil

Drivetrain Analysis and Optimization of a Two-Speed Class-4 Electric Delivery Truck

2019-01-50011/18/2019

The development, analysis, and comparison of battery electric class-4 medium-duty trucks equipped with three possible powertrain layouts, namely, direct drive, single-speed gearbox, and two-speed transmission options, are discussed in this paper. The problem definition is included and the performance evaluation criteria for the proposed truck architectures are defined, namely, acceleration time, top speed, and efficiency. Designs of four new traction motors are proposed and their benefits compared for use in medium-duty electric trucks (e-trucks). The procedure for gear-ratio range selection is outlined, the ranges of gear ratios for the single-speed gearbox and two-speed transmission powertrains being calculated for each of the proposed electric traction motors. The simulation and gear-ratio optimization tasks for the e-trucks are formulated. The energy consumption of the e-truck with the three possible powertrain combinations is minimized over the six driving cycles. The most efficient powertrain layouts that meet the performance criteria are determined.

Morozov, Alexei, Humphries, Kieran, Rahman, Tanvir, Zou, Ting, Angeles, Jorge

Design and Development of a Retrofit Solution for Converting a Conventional LCV into Parallel Hybrid Electric Vehicle

2019-26-01171/9/2019

In today’s scenario, the emission norms are getting stringent day by day due to an increased level of pollution. The world is shifting towards low carbon footprint which made it necessary to adopt efficient technologies with fewer emissions. The hybridization of vehicles has resulted in improved efficiency with lower emissions which can fulfil the near future emission norms. Retrofitting of hybrid components into a conventional IC engine vehicle is so far the best way to achieve better performance both economically and technologically. This research is primarily focused on the design and development of a novel retrofit solution of P3x architecture for the light commercial vehicle. This retrofit solution is different from other hybrid solutions in terms of powertrain. It contains an innovative add-on powertrain along with the existing powertrain. This additional powertrain consists of a pair of helical gears followed by a chain and sprocket as a coupler for traction motor. The newly designed powertrain provides 5 different hybrid modes namely engine only mode, electric only mode, motor assist mode, battery charging mode and regenerative braking mode. The retrofit work also focuses on packaging design of hybrid components into chassis ensuring that it can sustain all load transferring from road along with additional weight without failure. To demonstrate the practical applicability of this indigenous powertrain with P3x hybrid configuration, a prototype has been developed and functionally tested on chassis dynamometer. The driving performance and fuel economy of the developed prototype were virtually tested for MIDC drive cycle. The results demonstrate a noticeable improvement in fuel economy and increase in payload compared to conventional ICE vehicle.

Kumar, Ravindra, Kaundinya, Ashwin Subramanian, Shah, Ravindra, Ghugal, Swapnil, Kale, Jyoti Ganesh, Thorat, Vivek, Barik, Saroj, Shinde, Sanket

Development of 2 Speed Automatic Transmission for Battery Electric Two Wheelers

2019-26-01091/9/2019

Improving vehicle performance in terms of both torque and power is a strong customer need in both conventional and electric vehicles. In this work, different two speed automatic transmission (AT) concepts are developed to improve the energy efficiency and performance of battery electric two wheelers. Developed transmission systems are simple, compact and cost effective and results in relatively high energy efficiency of an electric motor. The unique shift control strategy ensures motor to operate at higher efficiency zones to minimize the overall energy consumption. Virtual simulations of electric vehicle were carried out for different driving conditions and optimal transmission ratios were determined. Mechanical behaviors such as gear shift characteristics, linear and angular velocities, inertial forces of each components are analyzed by using Multi body dynamics simulation. Forces predicted here are further used for durability studies of these components. The developed system combines superior shifting accuracy, high transmission efficiency with increased grade ability and results in substantial improvement in acceleration while retaining top vehicle speed without much compromise.

Satyanarayana, PS, Ayyappath, Prajod, Jaiswal, Animesh, Iyer, Ramkumar, Charantimath, Siddalingesh

Electric Vehicle with Multi-Speed Transmission: A Review on Performances and Complexities

08-07-02-001112/4/2018

Electric vehicles (EVs) with multi-speed transmission offer improved performances compared to those with single speed transmission system in terms of top speed, fast acceleration, or gradeability along with driving range. In this study, relevant literature is extensively analyzed to explore the performances and associated complexities with multi-speed automatic manual/mechanical transmission (AMT) system in EVs. In EV powertrain, the only torque generator component is electric motor, which is not equally efficient throughout wider speed range. To the other end, vehicles need to run at different speeds in diverse driving conditions. The study shows that multi-speed transmission system enables efficient operation of electric motor by choosing an appropriate gear at different driving torque-speed demands and thus contributes to achieve desired vehicle performances at minimum energy consumption. To demonstrate the differences, both dynamic and economic performances with multi-gear system and single speed system are compared, and the results of various techniques are presented in the form of tables and bar charts. A quantitative analysis is also conducted to show the performance improvement achievable by employing multi-speed transmission concept in EVs. Apart from additional mass, gear ratio selection and torque interruption during gear shifting are major obstacles to improve drivetrain efficiency and riding comfort in EVs with multi-speed transmission system. For optimal gear ratio in transmission system, genetic algorithm (GA) is found to be implemented in most articles. It is also observed that variable shift schedule needs to be considered during the optimization process to get the paramount gear ratios. Tables and bar charts are used to show the results of recent relevant works to these issues. In this article, the readers would gain a comprehensive knowledge on how multi-speed transmission technology can outperform the single speed system within EV platform and what the inherent challenges are.

Ahssan, Md Ragib, Ektesabi, Mehran Motamed, Gorji, Saman Asghari

Increase of Stability for Motor Cars in Service Braking

2018-01-188010/5/2018

New solutions for actual problems of determination the efficient distribution of braking forces between the axles of the vehicle, and the stability and drivability of two-axles vehicles at service braking are received in the thesis. It permitted for the first time to determine the Law of distribution of the braking forces between the axles, that ensuring straight-running stability of two-axle vehicle at service braking, to obtain the ideal characteristics for the braking system of two-axle vehicle at service braking and to determine possible values for the distribution of braking force on the front axle. The drivability criterion at service braking obtained further development; it is offered to use boundary at gripping front or rear wheels angular vehicle acceleration on the road. The application of the stability coefficient as one of the criteria for service braking efficiency allowed to determine the ideal, as for preserving the road-holding ability, Law of distribution of the braking forces between the axles. Despite the idea, if the vehicle deceleration is increased at service braking, the ideal coefficient of braking force distribution on the front axle should be decreased, but not be increased. At small decelerations, the given coefficient can be equal to one (rear wheels are not braked), and at the maximum decelerations - we should take into account the values that correspond to retain the front and rear wheels on the blocking limit. The area of rational values of the coefficient of braking force distribution on the front axle, limited by the curves of the ideal distribution of braking forces at service braking and limit values of the adhesion coefficient, and by straight line of the ideal distribution of braking forces at emergency braking are determined. The limit values of the vehicle deceleration at service braking are determined. If the limit values are lower than the given ones, it is necessary to carry out braking only with the front wheels brakes. The obtained ideal characteristics of the two-axles braking system allow to estimate braking dynamics at emergency and service braking on roads with different coefficient of adhesion. With constant distribution of braking forces between the axles the deceleration area boundaries in which the vehicle can retain the road-holding ability at service braking are defined. To assess the impact of disturbances on the road-holding ability of the vehicle at service braking, a new criterion, the coefficient of disturbing action is offered. If the criterion value does not exceed the stability coefficient, the vehicle is stable, otherwise it loses its stability.

Podrigalo, Mikhail, Turenko, Anatoliy, Bogomolov, Viktor, Klets, Dmytro, Sergiyenko, Oleg, Karpenko, Volodymyr, Gritsuk, Igor V., Turenko, Oleksandr, Korobko, Andrii, Bulgakov, Nickolay, Boboshko, Oleksandr

Improvement of the Assessment Methods for the Braking Dynamics with ABS Malfunction

2018-01-188110/5/2018

The bulk of automobiles are equipped with ABS currently. Having of automatic devices that prevent vehicle wheels from locking and skidding does not require consideration of the normal reactions on the front and rear vehicle axles wheels’ changes dynamics. However, ABS malfunction is possible for various reasons, and in this case the braking system must provide the safety vehicle braking. To provide this, it is necessary to return to the problem of choosing the rational braking forces distribution between the wheels of the front and rear axles. Analysis of known methods for determining the rational choice of the braking forces distribution between the axes made it possible to reveal a number of inaccuracies and contradictions, to which the following notes can be attributed: traditionally it is determined the limiting forces distribution on the wheels’ adhesion with the road in case of emergency braking, and according to its braking moments distribution, which does not take into account the influence of inertial masses, which are applied to the wheels; when the normal reactions on wheels and their redistribution between the axles are determining, the changing in the point of application of the braking force, during the wheels' locking, is not taking into account (when the wheels are unblocked, the braking force is applied to the wheel axle, and when the wheels are locked, the braking force is applied to the contact spot of the wheels with the road). The article deals with analytical expressions which allow to make a rational choice of the brake moments distribution between the front and rear wheels, taking into account the inertial masses of a powertrain. It is shown that the known law of the ideal distribution of tangential reactions between the axes corresponds to the automobile braking with all blocked wheels. If it is necessary to bring simultaneously the front and rear wheels to the blocking limit, then it will be necessary to choose another law of braking forces distribution between the axles, at which the front brakes are weakened and the rear brakes are strengthened. Simultaneous bringing to the blocking limit the front and rear wheels does not prevent locking of the rear wheels first. It is determined that in case of the ABS failure on the rear wheels and the normal work of the ABS on the front wheels, makes it possible to improve the stability of the automobile (compared to the ABS failure on the all wheels) by increasing the normal load on the rear wheels. The recommendations, which are given, can be useful at the development of automobile braking systems. They will allow increasing safety of automobile braking not only at АВS malfunction, but also at service braking when АВS is not working.

Podrigalo, Mikhail, Klets, Dmytro, Sergiyenko, Oleg, Gritsuk, Igor V., Soloviov, Oleh, Tarasov, Yuriy, Baitsur, Maksym, Bulgakov, Nickolay, Hatsko, Vasyl, Golovan, Andrii, Savchuk, Volodymyr, Ahieiev, Maksym, Bilousova, Tetiana

Millers Oils tackles EV lubrication challenges

18AUTP10_0910/1/2018

Although electric vehicles (EVs) often are extolled as “low-maintenance” alternatives to conventional internal-combustion (IC) propulsion and its brew of critical fluids that require routine maintenance, EV drivetrains also rely on proper lubrication-and in many senses pose performance challenges at least equal to those of IC drivetrains. Not the least of electric drivetrains' unique stresses on lubrication: electric motors can deliver maximum torque at zero rpm.

Birch, Stuart

Torsional Fluctuations Consideration while Design of Synchro Rings

2018-01-18239/10/2018

In today’s manual transmissions of car, gearshift system requires high performance with particular emphasis on low effort, minimal travel and positive feel. To meet these targets, a high capacity multi cone synchronizers along with higher co-efficient of friction material used for lower gears. The design of synchronizer with these specifications is influenced by torsional fluctuations from engine. Excessive torsional vibrations leads to wobbling of synchro rings within the peripheral clearances with surrounding parts. Wobbling leads to abrasion wear of frictional area of synchro ring causing grating or crashing noise of gears during shifting. This paper presents the optimization of the multiple cone synchronizer design exposed to excessive torsional vibrations and validation of the same on test bench during development stage instead vehicle level validation.

Tawhare, Nitin, Aswale, Dhananjay, Ponkshe, Makarand

GKN turns the CV joint inside-out

18AUTP09_099/1/2018

GKN Driveline is developing an innovative driveshaft concept that literally turns inside out the traditional configuration of the constant-velocity joint (CVJ), bringing potential benefits to both high-performance rear-wheel-drive vehicles-and future electric vehicles (EVs). In a conventional design, CVJ housings face outward from the sideshaft, while the sealing systems on each end face inward; GKN has been testing a layout in which the CVJ reverses the positions of these components within a sideshaft system, integrating the CVJ housings within the sideshaft itself.

Birch, Stuart

Exoskeletons, Surgical Robotics Drive Advances in Motion System Technologies

TBMG-297477/1/2018

New technologies are coming along every day that are designed to make an engineer's life easier when attempting to fulfill his or her motion control system needs. This article reviews some of the latest advances in motion control and presents an application in which all of these components can be used together.

Novel Three-Cylinder Engine Solutions Offering Low Noise Vibration and Harshness for Range-Extender and Hybrid Electric Vehicles

2018-01-15536/13/2018

In recent years, automotive manufacturers have introduced an increasing array of in-line three cylinder engine solutions with the objective of providing efficient low CO2 emission power train solutions for small vehicles and in some cases to address down-sizing targets. At the same time, three cylinder engines have seen recent introduction in range-extender and hybrid electric vehicles such as the BMW i8. Unfortunately in-line three cylinder units present serious challenge to engineers in terms of noise, vibration and harshness and this often yields criticism from customer perceptions. The in-line three-cylinder arrangement however does offer an attractive packaging solution for vehicles and an effective method of reducing overall vehicle cost. This paper presents analysis and modelling of a high durability three-cylinder two-stroke cycle engine, which could offer advantages in this competitive and challenging sector for small automotive power plants particularly from a noise, vibration and harshness perspective. The engine uses segregated scavenging to overcome the durability problems of conventional two-stroke cycle engines. Configurations are presented with and without balance shaft and compared with a four stroke engine solution. The novel ability to combine the balance shaft with an integrated rotary valve system controlling gas exchange whilst simultaneously countering the problem of the pitching couple that three cylinder engines traditionally suffer from. Modelling of the benefits of the technology to address NVH issues are presented and discussed.

Hooper, Peter R.

Effects of Unbalanced Magnetic Pull on NVH Performance of an Electric Drivetrain

2018-01-15046/13/2018

Designing well-performing electric drivetrains requires a comprehensive understanding of the electro-mechanical interactions. The paper investigates the effect of unbalanced magnetic pull (UMP) due to rotor eccentricity in a typical automotive electric driveline with an integrated interior permanent magnet (IPM) machine and a two-stage gearbox. The investigation couples electromagnetic finite element analysis in Cobham Opera with electromechanical drivetrain simulation, including gears, shafts, bearings and housing in RomaxDESIGNER. Gear force can deflect the rotor which causes UMP between the rotor and the stator. It is shown that UMP varies non-linearly with rotor offset and machine operating condition. Harmonic analysis is performed on torque and radial rotor force to quantify the influence of rotor shaft deflections and hence rotor eccentricity on the frequency content of both torsional and radial electromagnetic excitations. The effect of such excitations on the system NVH response is shown. The presented methodology illustrates how a coupled electromagnetic-mechanical simulation can be used to understand how electromagnetic excitations can penetrate the mechanical system and manifest as structural vibrations of the housing and mounts, leading to airborne and structure borne noise.

Veggia Bombardi, Federico, Atallah, Kais, Shahaj, Annabel, Michon, Melanie, Holehouse, Robert, James, Barry, Ilea, Dan

Coupled Vibration Prediction of Rotor-Airframe-Drivetrain-Engine Dynamics

F-0074-2018-12759

5/14/2018

ABSTRACT Comprehensive vibration analysis of a rotor-airframe-engine-drivetrain system using a time-domain modal coupling approach was conducted. Pair-wise couplings of components (airframe and drivetrain/engine) were performed to isolate the contribution of each component to the complete coupled system, and the effect of each component on blade loads and hub loads was studied. The drivetrain model is a 6-dof model consisting of inertia and torsional spring elements, while the airframe model is a NASTRAN superelement of a detailed finite element airframe model for a medium-lift utility helicopter. Drivetrain coupling resulted in elastic twist of the rotor shaft by less than 0.02 degrees, but there were noticeable reductions in the chordwise blade bending moments as well the 8/rev hub torque. The airframe coupling produced very small hub translation amplitudes, less than 5×10⁻⁴ inches, however it had a significant impact on the higher harmonic flap bending, increasing the 9/rev flap moment by up to 60% near the root.

Sidle, Stacy, Sridharan, Ananth, Chopra, Inderjit

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