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Dual-Mass Flywheel with Torque Limiter: An Effective Solution for Overtorque Suppression in Automotive Transmission

Politecnico di Torino-Enrico Galvagno, Alessandro Vigliani, Giuseppe Calenda
  • Technical Paper
  • 2020-01-1016
To be published on 2020-04-14 by SAE International in United States
During some critical maneuvers, transmission systems using Dual Mass Flywheel (DMF) may experience overtorques, which could lead to structural damages of the transmission components. In a dual mass flywheel, total inertia is divided into two parts: a primary mass connected to the engine and a secondary mass to the transmission. The torque delivered by the engine is transferred from one mass to the other through a drive plate and a set of arc springs, the latter absorbing the torsional oscillations coming from internal combustion engine and the shocks caused by fast clutch engagements. This paper investigates overtorque issues and proposes a solution based on a torque limiter, consisting of a friction clutch inserted between the two masses, that limits the maximum torque transmitted through it. The basic idea is to replace the classic flat drive plate with a tapered drive plate that functions as a Belleville spring. The experimental analysis carried out on dedicated benches has tested the elastic characteristic of the tapered drive plate, the durability of friction pads and the variation of the…
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Commercial Truck and Bus SAE Recommended Procedure for Vehicle Performance Prediction and Charting

Truck and Bus Powertrain Committee
  • Ground Vehicle Standard
  • J2188_201807
  • Current
Published 2018-07-25 by SAE International in United States
This SAE Recommended Practice takes into account modern standardized methods for collecting and summarizing data that has an effect on vehicle steady-state performance, such as engine output (gross and net), transmission losses, drivetrain efficiency, vehicle aerodynamic devices for various vehicle and body configurations, as well as road surface variations and air density variations resulting from altitude and barometric effects. The procedure does not address vehicle transient performance (acceleration, braking, and cornering), because of the considerable amount of additional data required such as moment of inertia of all the rotating parts. Nor does it address vehicles with torque converters and automatic transmissions. This document is, therefore, intended for vehicles having fixed-ratio type transmissions and positive engagement clutches. Metric and ISO unit conversions are provided in the metric conversion tables at the end of this procedure (see Appendix B). Some modern vehicles with electronic engine controls have the ability to vary the maximum engine revolutions for each gear, as well as permitting the power or rpm to increase if more time is spent in the lower gears,…
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Performance Evaluation of Magnetorheological Limited Slip Differential for Automotive Applications

Helwan University-Mohamed M. Abd elhafiz, H. Metered
Published 2018-04-03 by SAE International in United States
The present work investigates the effect of magnetorheological fluid (MRF) on limited slip differential (LSD) system for automotive applications to improve torque distribution which influences traction and maneuverability. The proposed differential system uses a magnetorheological fluid which permits to control the locking torque effectively and then improve the vehicle traction characteristics. To evaluate the proposed system, a prototype model involves some rotating clutches submerged in MRF associated with an electromagnet coil was built. Experimental tests were carried out in two cases, first case by applying mechanical force on the friction clutches and the second by applying magnetic field to change the MRF viscosity. The yield stress of MRF depends on the magnetic field applied by the electromagnet by varying electric current. The controllable yield stress generates friction force on the rotating clutches surfaces to transmit torque. The transmitted torque was measured to evaluate the advantages of MRF in classic LSD. The results reveal that proposed MR-LSD can improve automotive traction.
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GKN readies new 2-speed e-axle for 2020

Automotive Engineering: November 2017

Lindsay Brooke, Ian Adcock
  • Magazine Article
  • 17AUTP11_11
Published 2017-11-01 by SAE International in United States

Driveline-enhancement technology is hot these days, with Tier 1s rolling out new axle-disconnect, electric axle and light-weighting innovations in rapid cadence. In the vanguard of this trend is GKN Driveline, whose masterpiece Twinster dual-clutch differential imparted the 2016 Ford Focus RS and Range Rover Evoque dynamic torque vectoring functions across the entire speed range. That was followed by the company's eTwinster, bringing e-axle technologies pioneered in the Volvo XC90 T8 and other hybrids.

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Automotive Transmission Terminology

Automatic Transmission and Transaxle Committee
  • Ground Vehicle Standard
  • J645_201708
  • Current
Published 2017-08-25 by SAE International in United States
The following listed definitions are intended to establish terminology and criteria for describing the various kinds of automotive transmissions. A specific arrangement may be described by a combination of several of these definitions.
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A Guide to Aircraft Power Train Monitoring

E-32 Aerospace Propulsion Systems Health Management
  • Aerospace Standard
  • AIR4174A
  • Current
Published 2017-07-19 by SAE International in United States
The purpose of this SAE Aerospace Information Report (AIR) is to provide management, designers, and operators with information to assist them to decide what type of power train monitoring they desire. This document is to provide assistance in optimizing system complexity, performance and cost effectiveness. This document covers all power train elements from the point at which aircraft propulsion energy in a turbine or reciprocating engine is converted via a gear train to mechanical energy for propulsion purposes. The document covers aircraft engine driven transmission and gearbox components, their interfaces, drivetrain shafting, drive shaft hanger bearings, and associated rotating accessories, propellers, and rotor systems as shown in Figure 1. For guidance on monitoring additional engine components not addressed, herein (e.g., main shaft bearings and compressor/turbine rotors), refer to ARP1839. This document addresses rotary and fixed wing applications for rotor, turboprop, turbofan, prop fan, and lift fan drive trains on both commercial and military aircraft. Information is provided to assist in: a Defining technology maturity and application risk b Cost benefit analysis (Value analysis) c Selection…
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Oil Sheer Clutch Cuts Downtime for Metal Stamping Press

  • Magazine Article
  • TBMG-27074
Published 2017-06-01 by Tech Briefs Media Group in United States

In the metal stamping business, precision, repeatability, and uptime are key. But stamping accuracy suffers when improper tension on the coil feeders incorrectly supplies metal to the presses, resulting in off-spec parts and increased rejections. ART Technologies of Fairfield, OH, relies on an oil shear clutch brake to supply constant, reliable tension on the coil feeding to one of its 400-ton presses to produce the precision and repeatability it needs, with no downtime for maintenance or adjustment. When the plant is working 20 hours a day, that uptime is as critical as the tolerances it maintains.

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Road-efficient mud machine

Automotive Engineering: April 2017

Lindsay Brooke
  • Magazine Article
  • 17AUTP04_05
Published 2017-04-01 by SAE International in United States

Jeep's all-new 2017 Compass gets its go-anywhere guts from GKN's AWD system.

Replacing the decade-old Jeep Compass is the new-for-2017 Compass, FCA's (and Jeep's) first truly global vehicle program. Styled to resemble a slightly scaled-down Grand Cherokee, the new C-segment SUV is being produced in four plants (Mexico, China, India and Brazil) and offered in 17 powertrain combinations that include diesels and 6-speed manual gearboxes. The U.S. gets the manual ‘box but not the diesel.

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Novel Shift Control without Clutch Slip in Hybrid Transmissions

AVL LIST GmbH-Muammer Yolga, Markus Bachinger
Published 2017-03-28 by SAE International in United States
With the introduction of new regulations on emissions, fuel efficiency, driving cycles, etc. challenges for the powertrains are significantly increasing. In order to fulfil these regulations, hybrid-electric powertrains are an unquestioned option for short and long-term solutions. Hybridization however, is not only fulfilling these challenging efficiency or emission targets, but also allows numerous new possibilities on control strategies of different powertrain elements as well as new approaches of designing them. A good example is transmissions where, hybridization allows a new transmission type called Dedicated Hybrid Transmission (DHT), which enables to use novel control strategies bringing improved performance, driveability, durability and NVH behavior.This paper focuses on the novel shift strategy where friction clutches do not have to slip. The strategy introduces a novel shifting control using the integrated electric motor and special power flow of the dedicated hybrid transmissions. The novel shift strategy significantly improves shift comfort, thermal losses and element durability. In addition, several design aspects are challenged by proposing questions like selection of dog clutches over friction clutches, usage of eCVT modes in DHT…
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Development of Innovative Toyota 10-Speed Longitudinal Automatic Transmission

SAE International Journal of Engines

Toyota Motor Corporation-Seiji Masunaga, Terufumi Miyazaki, Yohei Habata, Kazuhiko Yamada, Yoshio Hasegawa, Takahiro Kondo, Ichiro Kitaori, Akira Takeichi
  • Journal Article
  • 2017-01-1099
Published 2017-03-28 by SAE International in United States
Toyota Motor Corporation has developed an innovative 10-speed longitudinal automatic transmission called the Direct Shift-10AT. The Direct Shift-10AT is a significant contributor to the excellent dynamic performance of the Lexus LC500. A wide gear spread with close gear ratios allows for rhythmical shifting, smooth and powerful acceleration from a standing start, along with quiet and relaxed high- speed driving due to low engine speeds. The lock-up area is expanded to a wider range of vehicle speeds (excluding low-speed regions such as when starting off), by the adoption of a multi-plate lock-up clutch, a newly developed torque converter, and a high-precision controller. As a result, the shift control can match the driver's intended operation more directly because the main cause of the response delay (transient changes in engine speed (flare)) is eliminated. Furthermore, fuel economy is improved due to the adoption of low friction clutches. Emotional driving performance is achieved using a support control that responds to the driver's intention and the driving situation, cooperative control with the powertrain, and one of the world's quickest shifting…
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