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Future hybrid Vehicles with advanced 48V electrified drive train technology to reduce Co2 emission

Mercedes-Benz R&D India Pvt Ltd-Chandrakant Palve, Pushkaraj Tilak
  • Technical Paper
  • 2019-28-2487
To be published on 2019-11-21 by SAE International in United States
Future hybrid vehicles with advanced 48V electrified drive train technology to reduce CO2 emission. Chandrakant Palve* Pushkaraj Tilak * * Mercedes-Benz Research & Development India Pvt. Ltd. Bangalore. India. Key Words: 48V, CO2, P3 Hybrid, Electrified powertrain, AMT, emission, shift comfort, motor Research and/or Engineering Questions/Objective Global automotive industry is putting effort in moving from conventional powertrain technology to hybrid & electric powertrains. This efforts plays a vital role to achieve cleaner environment, improved performance, reduced fossil-fuel dependency, low noise for meeting regulatory & customer requirements. Automotive industry is facing a challenge of meeting stringent CO2 emission targets of 95g & 175g per kilometer for passenger cars & light commercial vehicles respectively. 48V is an important stepping stone in this direction. By taking motivation from this strategic challenge, advanced 48V P3 electrified powertrain technology has been proposed. The objective of this research is a novel electrified powertrain which offers Dual Clutch Transmission (DCT) level of shift comfort in combine with CO2 benefit without additional cost and weight penalty. Methodology The present study describes a unique…
 

Design and Analysis of Hydrostatic Transmission (HST) system for OFF-Highway vehicle

ARAI-Rakesh Vilasrao Mulik, Ramdasi Sushil S, Neelkanth V Marathe
RIT-Siddhant JADHAV, Sanjaykumar Gawade PhD
  • Technical Paper
  • 2019-28-2453
To be published on 2019-11-21 by SAE International in United States
The development of any country depends on capital energy consumption. Due to technological advancements, people want more comfort and performance with the tractors and at the same time less fatigue and reduced fuel consumption. At present, most of the tractors uses conventional Manual Transmission (MT) as main driveline, though there is research going on, with implementation in few cases, for shifting from conventional MT to advanced transmissions. A Continuously Variable Transmission (CVT) provides Step Lesley an infinite number of effective gear ratios between maximum to minimum value. Hydrostatic Transmission (HST) is one of the types of CVT. HST can improve the fuel efficiency and smooth drivability than a MT without compromising vehicle performance. The development of HST in tractor is less costly as several existing components such as clutch, large number of gears in transmission system can be removed along with reducing of driver fatigue. HST has the ability to adjust engine speed at the point of maximum fuel efficiency for given speed and power requirement. HST includes the combination of at least one hydrostatic…
 

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…
 

Performance Analysis of an Automated Manual Transmission Controller for Two-wheeler

ARAI Academy-Kiran Pralhad Wani
CoEP-ARAI Academy-Saurabh Sunil Patil
  • Technical Paper
  • 2019-28-0125
To be published on 2019-10-11 by SAE International in United States
This research paper presents controller development and performance analysis for the two-wheeler. The comparison for different performance parameters is carried out with and without automated manual transmission (AMT) controller. The AMT considered, in this case, includes a conventional manual transmission gear-box with a conventional clutch pedal. It is equipped with clutch actuation with the help of linear actuator and the gear shifting using a servo motor. The upshift and downshifting of the gears and the clutch actuation is done through the decisions of the controller. The results generated during the engine dynamometer test are used as input creating a two-wheeler vehicle model using AVL cruise software. This vehicle model is used to predict vehicle performance. These vehicle performance results are validated with chassis dynamometer test data. The vehicle model is modified for the generation of gear shifting plot. AlsoGear shift program (GSP) is generated using the GSP generation module of AVL cruise software. The two criteria used for GSP generation are fuel economy and vehicle acceleration performance. The simulation results include generation of gear shifting…
 

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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Heavy-Duty Aerodynamic Testing for CO2 Certification: A Methodology Comparison

Intl. Council on Clean Transportation-J. Felipe Rodriguez, Oscar Delgado
University of Technology Graz-Martin Rexeis, Martin Röck
Published 2019-04-02 by SAE International in United States
Aerodynamic drag testing is a key component of the CO2 certification schemes for heavy-duty vehicles around the world. This paper presents and compares the regulatory approaches for measuring the drag coefficient of heavy-duty vehicles in Europe, which uses a constant-speed test, and in the United States and Canada, which use a coastdown test. Two European trucks and one North American truck were tested using the constant-speed and coastdown methods. When corrected to zero yaw angle, a difference of up to 12% was observed in the measured drag coefficients from the US coastdown procedure and the EU constant-speed test. The differences in the measured drag coefficient can be attributed, among others, to the assumptions in the speed-dependence of the tire rolling resistance and axle spin losses, the data post-processing required by each methodology, unaccounted frictional losses in the transmission, the behavior of the automated manual transmission during the coastdown run, and the yaw angle correction.
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Model Based Control of Synchronizers for Reducing Impacts during Sleeve to Gear Engagement

CEVT China Euro Vehicle Technology-Eva Barrientos, Henrique Budacs, Johan Hellsing
Chalmers University of Technology-Anders Grauers
Published 2019-04-02 by SAE International in United States
This paper presents a model based control strategy aimed to reduce noise and wear during gearshifts in conventional and hybrid Dual Clutch Transmissions (DCT and DCTH) and Automated Manual Transmissions (AMT). The control strategy is based on a newly developed dog teeth position sensor layout at China Euro Vehicle Technology AB (CEVT), a detailed simulation model for gear engagement and already existing speed sensors in the transmission. The details of dog teeth position sensor and simulation model are also presented in this paper. During gear shifting, noise is generated because of impacts between the sleeve teeth and the idler gear dog teeth after speed synchronization. Besides noise, these impacts are also responsible for delaying the completion of shift and contribute to wear in the dog teeth, hence reducing the lifespan of the transmission. The simulation model for gear engagement can simulate these impacts. Based on the simulation model and optimal control theory, an ideal dog teeth position trajectory is formulated that avoids the impact between sleeve and idler gear dog teeth, before the start of…
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A New Analytical Model for Clutch System Modeling and Design Optimization

Maruti Suzuki India Ltd.-Rahul Shandilya, Vikas Rawla
  • Technical Paper
  • 2019-01-0840
Published 2019-04-02 by SAE International in United States
In manual transmission vehicles, Clutch has direct interaction with the driver and plays a significant role in defining the drivability and NVH of a vehicle. These key performance factors depend on the interaction of diaphragm and cushion springs of a clutch. For an automobile manufacturer, it’s essential to optimize the characteristics of these springs based vehicle performance requirements. A state of the art analytical model has been developed by modeling the diaphragm and cushion spring with exponential equations. Based on these models, response functions for release load, torque build-up, and pressure plate lift have been derived. Results achieved from these response functions are correlated with test data. Key contributing factors for peak clutch pedal load, vehicle launch acceleration, and disengagement point have been identified by sensitivity analysis. Multi-objective optimization is performed to select optimized parameters for vehicle performance improvement
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Analytical Estimation of Clutch Life for Manual Transmission

Tata Motors, Ltd.-Anurag Mishra, Damodar Chollangi
Published 2019-04-02 by SAE International in United States
The clutch is the connecting link between engine and the power train. It connects and disconnects the engine to the gearbox as per the wish of the driver. Clutch has a friction disc which acts like a fuse wire which wears in the process of the connection. This paper tries to calculate the clutch life analytically (In terms of Kms. run by vehicle), of automotive vehicles having manual transmission. As the clutch engages and disengages the engine to the gearbox, during this time due to slippage, energy is dissipated which results in the wear of the clutch disc. It calculates life based on the volumetric wear of the clutch disc and wear allowance available. The work done by other people in this domain include the empirical estimation of clutch life based on the past data, effect of the surface topography on the friction characteristics of the wet clutches, modeling of clutch housing and facing temperature for the estimation of the clutch life of a manual transmission etc. The present work simplifies the estimation of clutch…
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Assessment through Numerical Simulation of the Impact of a 48 V Electric Supercharger on Performance and CO2 Emissions of a Gasoline Passenger Car

Politecnico di Torino-Alessandro Zanelli, Federico Millo
Röchling Automotive-Marco Barbolini, Luca Neri
Published 2019-04-02 by SAE International in United States
The demanding CO2 emission targets are fostering the development of downsized, turbocharged and electrified engines. In this context, the need for high boost level at low engine speed requires the exploration of dual stage boosting systems. At the same time, the increased electrification level of the vehicles enables the usage of electrified boosting systems aiming to exploit the opportunities of high levels of electric power and energy available on-board. The aim of this work is therefore to evaluate, through numerical simulation, the impact of a 48 V electric supercharger (eSC) on vehicle performance and fuel consumption over different transients. The virtual test rig employed for the analysis integrates a 1D CFD fast running engine model representative of a 1.5 L state-of-the-art gasoline engine featuring an eSC in series with the main turbocharger, a dual voltage electric network (12 V + 48 V), a six-speed manual transmission and a vehicle representative of a B-SUV segment car. The evaluation tests chosen for the case study were, on the one hand, vehicle elasticity manoeuvres for the performance assessment…
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