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Fuel efficiency improvement in automatic Transmissions by Lock-up clutch slip control methodology.

Mahindra & Mahindra, Ltd.-Arun Sukumar
  • Technical Paper
  • 2019-28-0029
To be published on 2019-10-11 by SAE International in United States
Introduction :- Nowdays, Automatic transmissions (AT) have taken over more in the automotive market. Because of traffic, frequently clutch pedal pressing and shift lever operation becomes annoyance in manual transmission.Automatic Transmissions (AT) has better driving comfort, simple operation, but a lower transmission efficiency, higher fuel consumption, can't be competed with manual transmissions. Fuel economy of Automatic Transmissions is poor especially in city drive (Because of driving @ low engine speeds where Torque Converter(TC) is opened). Objective :- The objective of this paper is to present a methodology for torque converter clutches (TCC) to enable clutch slip control at low engine speeds in torque converter without adversely affecting noise and vibration (N&V) performance and increasing fuel economy. The effect of gear state, torque converter slip and power delivered to the driveline on fuel economy are to be discussed. Lock-Up Slip Schedule Determination:- A reasonable slip control area is choosen for achieving increase in transmission efficiency, fuel economy and isolation of torsional vibration. 1. Running in first gear, the torque converter clutch must be unlocked to obtain…

Torque and Pressure CFD Correlation of a Torque Converter

SAE International Journal of Passenger Cars - Mechanical Systems

Ford Motor Company, USA-Steve Frait, Ram Devendran
Michigan Technological University, USA-Edward De Jesus Rivera, Mark Woodland, Darrell Robinette, Jason Blough, Carl Anderson
  • Journal Article
  • 06-12-03-0012
Published 2019-08-22 by SAE International in United States
A torque converter was instrumented with 29 pressure transducers inside five cavities under study (impeller, turbine, stator, clutch cavity between the pressure plate and the turbine shell). A computer model was created to establish correlation with measured torque and pressure. Torque errors between test and simulation were within 5% and K-Factor and torque ratio errors within 2%. Turbulence intensity on the computer model was used to simulate test conditions representing transmission low and high line pressure settings. When turbulence intensity was set to 5%, pressure simulation root mean square errors were within 11%-15% for the high line pressure setting and up to 34% for low line pressure setting. When turbulence intensity was increased to 50% for the low line pressure settings, a 6% reduced root mean square error in the pressure simulations was seen. For all pressure settings, cavities closer to the converter inlet required a 5% turbulence intensity while the cavities inside or near the torus were better suited with 50% turbulence intensity levels.

Testing Methods and Signal Processing Strategies for Automatic Transmission Transient Multiplexed Pressure Data

Ford Motor Company-Steve Frait, Ram Sudarsan Devendran
Michigan Technological University-Mark Woodland, Jason Blough, Darrell Robinette, Carl Anderson
Published 2019-06-05 by SAE International in United States
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.
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Systematic CFD Parameter Approach to Improve Torque Converter Simulation

SAE International Journal of Passenger Cars - Mechanical Systems

Ford Motor Co., USA-Steve Frait
Michigan Technological University, USA-Edward De Jesus Rivera, Darrell L. Robinette, Jason R. Blough, Carl L. Anderson
  • Journal Article
  • 06-12-02-0008
Published 2019-04-08 by SAE International in United States
A systematic parametrization approach was employed to simulate a torque converter operating over a wide range of speed ratios. Results of the simulation yielded torque converter impeller and turbine torques prediction errors below 11% when compared to manufacturer data. Further improvements in the computational fluids dynamic (CFD) model reduced such errors down to 3% for the impeller and 6% for the turbine torque predictions. Convergence was reached well under 300 iterations for the most optimal variable setting, but each speed ratio was let to run for 300 iterations. Solution time for the 300 iterations was 40 minutes per speed ratio. The systematic parametrization provides a very competitive procedure for torque converter simulation with reduced computational error and fast solution time.
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Model Order Reduction for x-In the Loop (xIL) Simulation of Automotive Transmissions

Ohio State University-Clayton Thomas, Punit Tulpule, Shawn Midlam-Mohler
Published 2019-04-02 by SAE International in United States
Increasing complexity of automotive systems along with growing safety and performance requirements, is causing development cycle costs to swell. A common solution is to use a Model-Based Design (MBD) approach, particularly using x-In the Loop (xIL) simulation methods for Validation and Verification (V&V). MBD allows efficient workflow from offline control design using high-fidelity models to real time V&V using Hardware-in-the-Loop (HIL) simulations. It is very challenging to reduce the complex non-linear high-fidelity models to real-time capable models for HIL simulation. Current literature does not provide a standard approach for obtaining the HIL-capable reduced model for complex non-linear systems. In this paper we present an approach to perform model reduction in light of HIL-level requirements. The approach is presented using an example of a 10-speed automatic transmission. The system constitutes three subsystems - the hydraulic network, mechanical gearbox, and torque converter. In the first step, a high-fidelity model for each subsystem is built up from the component level using one-dimensional mechanics and zero-dimensional hydraulic fluid flow. Secondly, the model is reduced gradually to meet the real-time…
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Development of a Compact and High-Performance Torque Converter Based on a New Parameter Sensitivity Mapping

JATCO Ltd-Kazunori Kawashima, Masatsugu Endo
Published 2019-04-02 by SAE International in United States
Automatic transmissions are required to obtain higher efficiency and to reduce their size and weight in order to improve environmental friendliness and fuel economy. Especially in the torque converter development process, there is a need to strengthen the torque multiplication capability to compensate driving force in the non-boost region as a result of recent trends toward engine downsizing. At the same time, there are more rigorous space-saving requirements from the standpoint of ensuring vehicle collision safety. To meet these various requirements, a new torque converter has been developed that provides world-class performance in a minimized torus size. The capacity factor and the torque ratio are the two major parameters of torque converter performance. There are many dimensional parameters concerning the blades and cross-sectional shapes of torus that must be considered in the performance design. It is difficult to optimize these parameters because they involve numerous tradeoffs. In this development project, the quantitative sensitivities between each of the parameters were broadly mapped. As a result, it was found that points existed in every parameter combination for…
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Ford engineers a tech barrage with 2020 Lincoln Aviator

Automotive Engineering: January 2019

Lindsay Brooke
  • Magazine Article
  • 19AUTP01_16
Published 2019-01-01 by SAE International in United States

Ford Motor Co. officially launched its 2020 Lincoln Aviator at the 2018 Los Angeles auto show, with the all-new three-row midsized luxury SUV featuring a barrage of equally new and significant technologies. Production is slated for 3Q 2019 at Ford's Chicago assembly complex.

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Airline Tow Tractor - Baggage/Cargo Factors for Design Consideration

AGE-3 Aircraft Ground Support Equipment Committee
  • Aerospace Standard
  • AIR1316B
  • Current
Published 2018-09-27 by SAE International in United States
This document outlines the functional and design requirements for baggage/cargo tow tractors used for airline services.
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Design Specification for Towbarless Tow Vehicles

AGE-3 Aircraft Ground Support Equipment Committee
  • Aerospace Standard
  • ARP4853D
  • Current
Published 2018-09-19 by SAE International in United States
The tow vehicle should be designed for towbarless movement of aircraft on the ground. The design will ensure that the unit will safely secure the aircraft nose landing gear within the coupling system for any operational mode.
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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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