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Virual Road Torque Data Collection Application

Tata Motors Ltd.-Dattatreyudu Mullapudi, Popat Rajput, Mithun Chaskar, Santosh Gosavi
  • Technical Paper
  • 2019-26-0289
To be published on 2019-01-19 by SAE International in United States
The traditional method of collecting the road torque data of a vehicle is by instrumenting and running the vehicle on different road terrains. In recent times, we are receiving repeated requests to conduct these exercises for a vehicle program based for its application and different powertrain configurations. Each of these measurements cost and consumes valuable resources of the company in collecting the data and analyzing the data. These challenges triggered us to develop an application, which will give us quick estimate of the required parameters from road torque measurements in the absence of physical prototype. The developed application will reduce the time required to conduct road torque measurements by quickly assessing the change in drivability performance with respect to the changes in different driveline parameters and to reduce the repetition of physical measurements in the cases of update in engine calibration for the vehicles built for different applications. The scope of this work is to estimate the demand torque at the driver wheels, gearshift pattern and gear utilization percentage of a vehicle by taking the…

Effect Of Ambient Temperature And Inflation Pressure On Tire Temperature

Automotive Research Association of India-Shreyas Bharadwaj, Vyankatesh Khairatkar
  • Technical Paper
  • 2019-26-0360
To be published on 2019-01-19 by SAE International in United States
Tire failure is identified as a major cause of accidents on highways around the world in the recent past. A tire burst leads to loss of control of the vehicle which ends up in a catastrophe. There are various factors which are accounted for a tire burst. Heat buildup, ageing of tire and cracks on tires are the major ones which are identified. A superior ability of the tire to dissipate the heat generated during operation is a major factor which prevents a tire failure. Other factors such as ambient temperature, inflation pressure etc. contributes to heat buildup which may ultimately result in tire failure. A combination of these factors might manifest as a tire failure at high speeds, the latter being an immediate cause of heat buildup. A dormant crack in the tire might develop if the temperature and pressure conditions are favorable, thus giving away at the weakest point. With regard to the temperature conditions, road conditions, inflation pressure checks etc. India is vulnerable to tire failures. It may be noted that present…

Analysis of Effect of the Tire Inflation Pressure, Inflation Fluids, Load and Speed on Tire Performance

Rajarambapu Institute of Technology-Dhananjay Ganpati Thombare
  • Technical Paper
  • 2019-26-0368
To be published on 2019-01-19 by SAE International in United States
There are various losses associated with passenger vehicle that affect its fuel economy as it is being operated. These losses include engine, driveline, aerodynamic and rolling losses. While engine, driveline and aerodynamic losses are inherent with the vehicle due to large number of parts that go into assembling, rolling loss is associated with the vehicle tires and it is the only part of the vehicle that comes in contact with the road. The rolling resistance of inflated tires is an important component of rolling resistance to vehicle motion and contributes to vehicle fuel consumption. Hence the effect of tire parameters such as inflation pressure, speed and load are the subject of much current interest. Also effect of type of inflation fluid on tire performance is a need of investigation. This work is focused on the design and development of tire testing setup to test the tire performance parameters like rolling resistance and tire temperature by varying the load, speed, inflation pressure and inflation fluids. Tire 135/70 R12 65 S has selected for testing. The test…

External Aerodynamic Drag Coefficient Prediction of Full-scale Passenger Car Based on Scale Model Assessment.

Tata Motors, Ltd.-Rohan Arun Gulavani, Sujit Chalipat, Amit Dighe, Faisal Anwar
  • Technical Paper
  • 2019-26-0224
To be published on 2019-01-19 by SAE International in United States
Aerodynamics performance evaluation of passenger cars is important during early vehicle development phase as it influences fuel economy, vehicle stability and drivability. Usually during initial styling phase, scale model are prepared and tested in wind tunnel to check aerodynamic performance like drag coefficient and these are used to predict aerodynamic performance of full scale model as testing on full scale model is costly and time consuming. To ensure its rightness, it is important to understand difference in physics from scale model to full scale model. In predicting full vehicle aerodynamics performance from scale model test; importance of Reynolds number, effect of geometric scaling on flow i.e. flow separation and wake zone change needs to be understood and addressed. This paper discuss about effect of scaling on aerodynamic flow behavior and drag. Further, with detailed flow behavior analysis, conclusions are derived on parameters that need to be scaled or addressed to predict full vehicle level drag from scale model. Study is carried out on three standard bodies i.e. notchback, estate back and fast back through computational…

Development and Prediction of Vehicle Drag Coefficient Using OpenFoam CFD Tool

Tata Motors, Ltd.-Kundan Biswas, Ganesh Gadekar, Sujit Chalipat
  • Technical Paper
  • 2019-26-0235
To be published on 2019-01-19 by SAE International in United States
Vehicle aerodynamic design has a critical impact on fuel efficiency of the vehicle. Reducing aerodynamic wind resistance of the vehicle's exterior shape and reducing losses associated with requirements for engine compartment cooling through vehicle front openings plays key role in achieving desired aerodynamic efficiency. Today fairly large number of computational fluid dynamics (CFD) simulations being performed during the vehicle aerodynamic design and development process and it is rapidly increasing day by day. Vehicle aerodynamic design and development process involves mainly aerodynamic shape development, aerodynamic optimizations of vehicle external components (side view mirror, spoilers, underbody shield etc.) and number of” what if studies during preliminary design process. Licensing costs of the available commercial CFD simulation solver has significance impact on product development cost when numbers of aerodynamic simulations expand. To address this aspects, open source code “OpenFoam” CFD have become popular in the aerodynamic community. This papers summarizes CFD simulation results for three standard Mira body configurations (Notchback, Fastback and Estateback) using OpenFoam solver. In this study, steady state simulations with Realizable K-epsilon and SST K-omega…

Methodology Development for External Aerodynamic Evaluation of a Bus and its impact on Fuel Economy along with Experimental Validation

ARAI-Kishor Udawant, Mahesh Patwardhan
Vellore Institute of Technology-Siddhesh Kanekar
  • Technical Paper
  • 2019-26-0294
To be published on 2019-01-19 by SAE International in United States
The objective of this study is to develop, demonstrate and validate the methodology of external aerodynamic analysis of a State Road Transport bus for prediction of drag coefficient and its impact on fuel consumption with experimental validation. It has been proven experimentally that vehicle consumes almost 40% of the available useful engine power to overcome the drag resistance. This provides us a huge scope to study the influence of aerodynamic drag. Baseline model of State Road Transport was evaluated for estimating fuel consumption using Computational Fluid dynamics (CFD) methodology. The CFD results were validated with the experimental data with less than 10 % deviation. Bus design was optimized with an objective of reducing the fuel consumption with parameters like angle of windshield, front chamfer and rear draft angle. Optimized bus design is also ensured to meet functional specifications as per AIS052. The prototype of the optimized bus design has been tested experimentally as per IS 11921: 1993 standard to estimate fuel consumption. The results obtained from CFD and experimental tests were analyzed and they were…

Electro-Magnetic Parking Brake System for Electric Vehicles

Tata Motors, Ltd.-Mani Paul, Kapil Baidya, Deepak R
  • Technical Paper
  • 2019-26-0119
To be published on 2019-01-19 by SAE International in United States
Regular vehicle has the advantage of Engine resistance even when it is not fired, hence vehicle roll back will not happen. This is not the case for Electric vehicles, which uses an electric motor, which does not have any resistance offered to wheels that prevent vehicle roll back on gradient. This leads to increased load on hydraulic brakes due to absence of engine inertia. Hence, there is a need for a low cost and reliable automatic braking system which can help in holding the vehicle and assists the driver during launch in case he need s to stop at a gradient. An Electromagnetic brake (EM brake) system can be used as a solution for the above-mentioned requirement. EM brake can provide hill hold and hill assist effect in addition automatic parking brake application when the vehicle is turned-off. This system will assist anyone who need to halt the vehicle at a gradient and then relaunch without much struggle. During emergency conditions, if the EM brake is nor disengaging automatically, a manual brake release system can…

Prediction of Oil Flow inside Tractor Transmission for Splash Type Lubrication

Mahindra & Mahindra Ltd-Tanmay Sushant Santra, Kumar Raju, Rahul Deshmukh, Udaya Paradarami, Ayush Agrawal
Mahindra Research Valley-Nagarajan Gopinathan
  • Technical Paper
  • 2019-26-0082
To be published on 2019-01-19 by SAE International in United States
Automotive transmissions convert power from the engine into the optimum drive force and engine speed, and to transmit this drive force to the driveshaft. Structural components of the transmission get damaged or degraded due to wear and heat. Effective lubrication prevents this metal to metal contact. In addition, the lubricants also act as a thermal medium to effectively dissipate the heat produced due to frictional resistances. In many cases, it is not possible to adequately study oil flow even in physical tests due to the adherence of oil to the internal walls of the housing, excessive foaming of the oil and the obscuring of the flow by parts. Simulations provides an insight to the designer about the lubrication pattern, around the gear and housings otherwise challenging to analyze during actual test. This paper, provides a rapid and accurate methodology for tractor transmission to visualize the splashing pattern & oil reach to the bearing. The entire transmission unit is considered for the analysis to study the cumulative effect of the motion of all the gears on…

After Market Portable Drag Enablers to Improve Fuel Economy of on Road Car

General Motors Technical Center India-Pawan Kumar, Irshad Mahammad
  • Technical Paper
  • 2019-26-0261
To be published on 2019-01-19 by SAE International in United States
Abstract Aerodynamic performance of on-road vehicle can be improved by using portable enablers on rear portion of the vehicle which can be attached or detached by the owner himself. Objective of this study is to explore the possibility of using such portable enablers to substantially reduce the drag of the vehicle. Enablers with specific convex shapes are created on various positions of rear portion of vehicle and simulated with CFD solver FLUENT. Compact sedan vehicle was considered in this study. Preprocessing is performed and specific fluid domains are captured. Generally, aerodynamic enablers are integrated parts of the vehicle. This paper emphasizes on consideration of portable enablers which can be used while cruising for longer distances. Drag improvement of ΔCD=0.006~0.009 (6-9 counts) was achieved by introducing the specific enabler based on its position, shape and dimension. This paper also suggests methods of attachment of portable enabler to the vehicle. Simulation is performed using realizable k-ε model with non-equilibrium wall functions for turbulence modeling .Drag due to heat exchangers is included in the total drag of the…

Phenomenological Traffic Simulation as a Basis for an RDE Development Methodology

IPG Automotive GmbH-Jochen Petters, Guanlin Gao, Christian Donn, Wolfgang Zulehner
  • Technical Paper
  • 2019-26-0346
To be published on 2019-01-19 by SAE International in United States
Pollutant emission and the fuel consumption of vehicles are increasingly becoming the focus of public and legislative attention. According to the Euro 6d standard, vehicles must comply with emission limits on the test bench and on the road. This paper discusses a methodology that enables RDE compliance and robustness testing of engines and propulsion systems based on phenomenological traffic simulation on the test bench. The method is based on a road-to-rig approach. A real route is digitized and a virtual prototype of the target vehicle is built that models the driving resistances and properties of the real prototype. After comparing the speed profile to a real measurement, the robustness evaluation using variations can begin. Traffic has a major impact on the result. In order to take a diverse range of traffic situations into account for the robustness evaluation, an approach to phenomenological traffic simulation was developed that does not require a complex definition of virtual traffic objects. The traffic situations are modeled by means of artificial road signs on the route. Within the boundary conditions,…