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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…

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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An Optimal Gear Shifting Strategy for Minimizing Fuel Consumption Based on Engine Optimum Operation Line

Babol Noshirvani University of Technology-Kamyar Nikzadfar, Nima Bakhshinezhad, S. Ali MirMohammadSadeghi, Hossein Taheri Ledari, Alireza Fathi
Published 2019-05-21 by SAE International in United States
The increasing numbers of vehicles with limited fossil fuel resources, on the one hand, and the growing level of stringent regulations on exhaust emissions, on the other hand, have galvanized automotive industries and researchers into developing solutions for more efficient vehicles. Notwithstanding the recent developments in powertrain technologies, driving behavior is still an important attribute in lowering fuel consumption. Gear shifting strategy is a staple aspect of driving behavior that affects fuel consumption and engine emissions to a large extent in both manual and automated transmission systems. According to the definition of Optimum Operating Line (OOL), this article intends to illustrate that the closer the engine operating points to the OOL, the more efficient the driving. An optimal gear-shifting strategy is presented to minimize fuel consumption and number of gear shifts while maximizing drivability in the new European driving cycle (NEDC). In order to limit the engine operating region close to the OOL, a multi-objective grid search method is used to design the two square-root-like curves (two shifting thresholds), on both sides of the OOL,…
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Open Access

Energy-Efficient Cooperative Adaptive Cruise Control with Receding Horizon of Traffic, Route Topology, and Traffic Light Information

SAE International Journal of Connected and Automated Vehicles

AVL List GmbH, Austria-Alejandro Ferreira Parrilla, Stephen John Jones
Chalmers University of Technology, Sweden-Anders Grauers
  • Journal Article
  • 12-02-02-0006
Published 2019-05-16 by SAE International in United States
Advanced and cooperative vehicle (semi-) autonomous driving systems will become a necessity in the future for sustainable, convenient, and safe mobility. By utilizing Vehicle-to-Vehicle (V2V) and Vehicle-to-Infrastructure (V2I) communication, a vehicle’s energy consumption can be reduced while maintaining safety and driving comfort. A holistic control strategy is presented, which in a novel way incorporates traffic lights, road speed limits, gradients, and curvature, as well as surrounding traffic and detailed powertrain characteristics into a single Model Predictive Control formulation. The performance of the system is evaluated using a realistic co-simulation toolchain representing the vehicle, driver, and road, including complex traffic conditions. The approach is valid for a wide range of scenarios, ranging from urban city driving to highways. Simulation results for a D-class passenger car with a diesel engine and an automatic transmission in an urban route show energy savings between 5% and 30% with an unchanged travel time, compared to a simulated human driver.

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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Benchmarking a 2018 Toyota Camry 2.5-Liter Atkinson Cycle Engine with Cooled-EGR

Southwest Research Institute-Josh Alden
US Environmental Protection Agency-John Kargul, Mark Stuhldreher, Daniel Barba, Charles Schenk, Stanislav Bohac, Joseph McDonald, Paul Dekraker
Published 2019-04-02 by SAE International in United States
As part of the U.S. Environmental Protection Agency’s (EPA’s) continuing assessment of advanced light-duty automotive technologies in support of regulatory and compliance programs, a 2018 Toyota Camry A25A-FKS 4-cylinder, 2.5-liter, naturally aspirated, Atkinson Cycle engine with cooled exhaust gas recirculation (cEGR) was benchmarked. The engine was tested on an engine dynamometer with and without its 8-speed automatic transmission, and with the engine wiring harness tethered to a complete vehicle parked outside of the test cell. Engine and transmission torque, fuel flow, key engine temperatures and pressures, onboard diagnostics (OBD) data, and Controller Area Network (CAN) bus data were recorded. This paper documents the test results under idle, low, medium, and high load engine operation. Motoring torque, wide open throttle (WOT) torque and fuel consumption are measured during transient operation using both EPA Tier 2 and Tier 3 test fuels. The design and performance of this 2018 2.5-liter engine is described and compared to Toyota’s published data and to EPA’s previous projections of the efficiency of an Atkinson Cycle engine with cEGR. The Brake Thermal Efficiency…
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Development of Electric Oil Pump Controller in Hybrid Vehicle Based on PMSM (Permanent Magnet Synchronous Motor) and the AUTOSAR Platform

ETAS Korea-Hojeong Yoo
Hyundai & Kia Motor Corp.-Gyeongcheol Kim
Published 2019-04-02 by SAE International in United States
Traditional hybrid vehicles operated two types of oil pump, mechanical for combustion engine and electrical for electric motor, to supply oil pressure for automatic transmission in each power source. New hybrid vehicles has only one electrical pump to reduce system volume and to improve fuel efficiency. Purposes of this study are to make standardization of firmware development process for oil pump unit (OPU) and electric oil pump (EOP) and to apply permanent magnet synchronous motor (PMSM) instead of brushless DC (BLDC) motor. In old-fashioned non-operating system (OS) firmware, it was convenient to calculate control timing for motor control, however the firmware was deeply dependent to specific microcontroller Unit (MCU). In other words, much of efforts and time are needed if new MCU were applied. In this study, new standard development process for MCU firmware can be built up based on automotive open system architecture (AUTOSAR) platform by developing specific motor complex device driver (CDD). In existing system, the OPU supplied with high-voltage from battery drives the BLDC motor driven with six-step block commutation method through…
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Acceleration Testing of 2000 Van Hool 45 Foot Motor Coach

Collision Engineering Associates Inc.-Wesley Grimes, Jonathan Balasa
Wilcoxson Consulting LLC-Greg Wilcoxson
Published 2019-04-02 by SAE International in United States
The time/distance relationship for a motor coach accelerating from a stop is often needed to accurately assess the events leading up to a collision. Several series of tests were conducted to document the low speed acceleration performance of a 45 foot long 2000 Van Hool motor coach equipped with a Cummins ISM engine and an Allison B500 6-speed automatic transmission. These tests included three load configurations and two different acceleration rates, normal and rapid. Data were gathered with a Racelogic VBOX IIIi.
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Development of a Cone CVT by SDPD and Topology Optimization

Purdue School of Engineering & Technology-Nikhil S. Patil, Ehsan Malekipour, Hazim El-Mounayri
Published 2019-04-02 by SAE International in United States
The automotive industries have undergone a massive change in the last few decades. Nowadays, automotive industries and OEM manufacturers implement various innovative ideas to ensure the desired comfort while minimizing the cost, weight, and manufacturing time. Transmission system plays a major role in the aforementioned items. This paper aims to develop a conical roller with belt Continuously Variable Transmission (CVT) System by employing the System Driven Product Development (SDPD) approach and topology optimization of its traditional design. Furthermore, this paper explains the design steps of the CVT and its advantages and limitations compared with the other automatic transmission systems.
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Sensor Selection for Selective Clutch Fault Isolation in Automatic Transmissions Based on Degree of Fault Tolerance

Ford Motor Co., Ltd.-Majed Mohammed, Richard Hathaway, Abigail A. Henning
Ohio State University-Eeshan Vijay Deosthale, Qadeer Ahmed, Giorgio Rizzoni
Published 2019-04-02 by SAE International in United States
Multiple clutches are engaged to achieve a specific gear ratio in an automatic transmission (AT). When an engaged clutch loses pressure during the AT operation, it is classified as a clutch stuck off fault. Automatic transmissions can enter in neutral states because of these faults and the vehicle can lose power at the wheels. Our previous work describes a systematic way of performing sensor placement analysis for diagnosis of clutch faults in automatic transmissions. In this paper, we approach the issue from the point of view similar to that of functional safety according to the ISO 26262 standard; where a transmission functional safety concept should address transitioning to a safe state in case of hazards associated with stuck off clutches. We try to address the questions whether all the faults really need to be isolated from each other and whether it is possible to isolate only a subset of faults to reduce the number of required sensors and still maintain a reasonable performance/safety. A way to classify clutch faults based on fault tolerant actions and…
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