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Technical Paper

A Low Cost Euro-III Development Strategy for 4 L Engine for Commercial Vehicle Application

2006-10-16
2006-01-3384
Reduction of NOx (Oxides of Nitrogen) and particulates from engine exhaust is one of the prime considerations in current research and development in automotive industry. The present paper describes the combustion optimization done on a four cylinder, 4 liter DI diesel engine to meet stringent Euro-III emission norms. The engine FIE (Fuel Injection Equipment) and injector geometry was optimized for performance and emission. Smoke measurements were considered as indicative of soot, to predict particulate emissions. This was done to simplify the overall process and save development time. It was concluded that by combining the flexibility of electronically controlled fuel injection begin, with improved nozzle technologies, with higher spray velocities and spray penetration, a considerable reduction in NOx and particulate emissions can be achieved. This can serve as a low cost solution, without any exhaust after-treatment systems.
Technical Paper

Design of Commercial Vehicle Cooling Packages

2008-04-14
2008-01-0264
Optimization of vehicle engine cooling package with requisite heat rejection capacity plays a key role in achieving most fuel economy and also in meeting the stringent noise norms. A set of design and operating features from existing vehicle engine cooling systems is reviewed and evaluated for their potential to provide optimized engine cooling. The features reviewed states significant potential in engine performance but these are balanced by satisfying required engine cooling requirement. Sets of trials are carried out on said vehicle with dissimilar features of cooling packages and the results are evaluated. Fuel economy trials in performance mode are carried out on vehicle with well thought-out cooling package for healthier comparison.
Technical Paper

Design of Cabin Suspension Characteristics of Heavy Commercial Vehicle

2008-04-14
2008-01-0265
In the commercial vehicle business, Tractor-trailer combination vehicles are mostly used for carrying heavy loads for longer distances. To improve operating economy of the vehicle by reducing turn around time, it becomes a necessity to have a better driving comfort level for the vehicles. In a Tractor-trailer combination vehicle, due to point load acting on the tractor, pitching effect on the cab is very dominant. To overcome this pitching effect, a fully suspended cabin (suspended at four points) has been designed in order to have better ride comfort as compared to the fixed cabin. This paper discusses some of the measures taken to reduce the overall cabin pitching effect on Tractor -trailer combination vehicles.
Technical Paper

Suspension Testing using Wheel Forces on a 3 DOF Road Load Simulator

2008-04-14
2008-01-0223
The use of Wheel Force Transducers (WFTs) to acquire data for laboratory simulation is becoming standard industry practice. However, in test rigs where we have only the suspension module and not the complete vehicle, does the reproduction of the orthogonal forces and moments at the wheel centre guarantee an accurate replication of the fatigue damage in the suspension components? The objective of this paper is to review the simulation methodology for a highly non-linear suspension in a 3 DOF (degree-of-freedom) suspension test rig in which the simulation was carried out using only the three orthogonal loads and vertical displacement. The damage at critical locations in the suspension is compared with that on the road and an assessment of the simulation using the WFT is made based on a comparison of the damage on the road vs. the rig.
Technical Paper

Approach for Dynamic Analysis of Automotive Exhaust System

2008-10-07
2008-01-2666
The automotive industry is heading in the direction of signing off the exhaust system durability based on computer simulation rather than rig simulation and physical vehicle testing. This is due to the cost, time and availability of prototype vehicles and test track. Use of Finite Element Method (FEM) enables to assure the structural integrity of the exhaust system and also contribute to better understanding of the system behavior in the various operating conditions and evaluation of structural strength. This paper deals with dynamic analysis of a modular automotive exhaust system where it is directly mounted on power train pack. Selection of dynamic loads, processing of the test data, and effect of assembly loads along with material property variation due to temperature are explained. It also includes validation of the CAE model, prediction of probable failure locations and improving the design based on analysis outcome.
Technical Paper

“Dynamic Analysis of Cabin Tilting System of Heavy Trucks Using ADAMS-View for Development of a Software Interface for Optimization”

2008-10-07
2008-01-2683
Design of a Cabin Tilting System of heavy trucks, a multi degree of freedom mechanism, is a challenge. Factors like adequate tilting angle, cabin styling, packaging, non interference of tilting system with ride comfort, forces in the system, specifications of the hydraulic system, are all very important for designing the system. Numerous considerations make the design process highly iterative hence longer design time. This paper primarily focuses on Kinematics and Dynamic analysis of the system in ADAMS and validation of system with real time testing results. Intention of this work is to make a parametric ADAMS model and link it to a Knowledge Based Engineering application to facilitate designer to quickly carry out design iterations for reducing development time. The Knowledge Based Engineering software is made using object oriented language called ‘Object Definition Language’ which has been developed using C and C++ software languages.
Technical Paper

Development of IT Enabled System for Data Management to Meet EU Vehicle Recyclability Directives

2010-04-12
2010-01-0276
EU directive 2005/64/EC on type approval of motor vehicles with respect to their Reusability, Recyclability and Recoverability ( RRR ) requires vehicle manufacturers to put in place the necessary arrangements and procedures for Parts, Materials and Weight (PMW ) data collection from full chain of supply. This is required to perform the calculations of recyclability rate and recoverability rate in line with ISO 22628. Commonly practiced data collection methodologies included spreadsheet and use of internationally available IT support system for collection of material data. Data complexity and prohibitive cost for using Internationally available IT Support systems like IMDS (International Material Data System) has led to the in-house development of IT enabled Solution customizing Siemens PLM software product (Team centre Enterprise) and SAP (SRM suite).
Technical Paper

Structure Borne Noise and Vibration Reduction of a Sports Utility Vehicle by Body-Mount Dynamic Stiffness Optimization

2011-05-17
2011-01-1599
Among the key parameters that decide the success of a vehicle in today's competitive market are quietness of passenger cabin (in respect of both airborne and structure-borne noise) and low levels of disturbing vibration felt by the occupants. To control these values in body-on-frame construction vehicles, it is necessary to identify major transfer paths and optimize the isolation characteristics of the elastomeric mounts placed at several locations between a frame and the enclosed passenger cabin of the vehicle. These body mounts play a dominant role in controlling the structure-borne noise and vibrations at floor and seat rails resulting from engine and driveline excitations, and they are also a vital element in the vehicle ride comfort tuning across a wide frequency range. In the work described in this paper, transfer path tracking was used to identify root cause for the higher noise and vibration levels of a diesel-powered sports utility vehicle.
Technical Paper

Optimizing Steering Column Layout and UJ Phase Angle to Enhance Vehicle Dynamics Performance

2019-02-05
2019-01-5010
Vehicle dynamics is one of the most important vehicle attributes. It is classified into three domains, the longitudinal, vertical, and lateral dynamics. This paper focuses on optimizing the lateral vehicle dynamics which is driven by the straight ahead controllability and cornering controllability of the vehicle. One of the important parameters that dictates these sub-attributes is the steering ratio. Therefore, designing the right steering ratio is critical to meet the vehicle “specific” targets. Significant amount of work has been done by many researchers on variable steering ratio by implementing variable gear ratio (VGR) rack, active steering, and steer-by-wire systems. This paper discusses the methodology and considerations to optimize the steering ratio for a constant gear ratio rack by optimizing the steering column layout, viz., orientation and the phase angle in universal joints.
Technical Paper

Virtual Road Torque Data Collection

2019-01-09
2019-26-0289
The traditional method of collecting the Road Torque Data of a vehicle is by instrumenting and running the vehicle on different road terrains. Every time, physical testing becomes tedious & most challenging task due to unavailability of unit under tests, kind of resource required and so on. However, in view of response to the fast emerging technology & limit less competition, it has become mandatory to develop & launch products in market within no time. In recent times, there is increased demand for physical road torque data measurements for a vehicle program based on its application and different powertrain configurations, which clearly shows that unless we front load the data to design it is practically impossible to meet the deadlines. Each of these measurements cost and consumes valuable resources of the company in collecting and analyzing the data.
Technical Paper

Development of Hydrogen Fuel Cell Bus Technology for Urban Transport in India

2019-01-09
2019-26-0092
Polymer Electrolyte Membrane Fuel Cell (PEMFC) technology is considered for automotive applications due to rapid start up, energy efficiency, high power density and less maintenance. In line with National Hydrogen Energy Roadmap of Govt. of India that aims to develop and demonstrate hydrogen powered IC engine and fuel cell based vehicle. TATA Motors Ltd. has designed, developed and successfully demonstrated “Low Floor Hydrogen Fuel Cell Bus” which comprises of integrated fuel cell power system, hydrogen storage and dispensing system. The fuel cell power system, converts the stored chemical energy in the hydrogen to DC electrical energy. The power generated is regulated and used for powering the traction motor. The development of fuel cell bus consists of five stages: Powertrain sizing as per vehicle performance targets, fuel cell stack selection and balance of plant design and development, bus integration, hydrogen refueling infrastructure creation and testing of fuel cell bus.
Technical Paper

A Feedback and Feedforward Control Algorithm for a Manual Transmission Vehicle Simulation Model

2018-04-03
2018-01-1356
Authors were challenged with a task of developing a full vehicle simulation model, with a target to simulate the electrical system performance and perform digital tests like Battery Charge Balance, in addition to the fuel efficiency estimation. A vehicle is a complicated problem or domain to model, due to the complexities of subsystems. Even more difficult task is to have a control algorithm which controls the vehicle model with the required control signals to follow the test specification. Particularly, simulating the control of a vehicle with a manual transmission is complicated due to many associated control signals (Throttle, Brake and Clutch) and interruptions like gear changes. In this paper, the development of a full vehicle model aimed at the assessment of electrical system performance of the vehicle is discussed in brief.
Technical Paper

An Engine Stop Start System with Driver Behavior Learning and Adaption for Improving the User Experience

2018-04-03
2018-01-0609
Engine Stop/Start System (ESS) promises to reduce greenhouse emissions and improve fuel economy of vehicles. Previous work of the Authors was concentrated on bridging the gap of improvement in fuel economy promised by ESS under standard laboratory conditions and actual driving conditions. Findings from the practical studies lead to a conclusion that ESS is not so popular among the customers, due to the complexities of the system operation and poor integration of the system design with the driver behavior. In addition, due to various functional safety requirements, and traffic conditions, actual benefits of ESS are reduced. A modified control algorithm was proposed and proven for the local driving conditions in India. The ways in which a given driver behaves on the controls of the vehicles like Clutch and Brake Pedals, Gear Shift Lever were not uniform across the demography of study and varied significantly.
Journal Article

Study of Frequency Characteristics of Vehicle Motions for the Derivation of Inherent Jerk

2016-04-05
2016-01-1681
Jerk in a vehicle is a feel of user which appears due to sudden acceleration changes. The amplitude and frequency components of the jerk defines quality of an engine or an AMT calibration tuning. Traditional jerk evaluation methods use amplitude (peak) of the jerk as a performance index and its frequencies are either used as weighing factor with amplitude or not taken into account. A method is proposed in this paper to quantify and differentiate the non-acceptable level of jerk which is perceivable to human body. Jerk is obtained by differentiating the acceleration data which contains the frequencies in the lower to higher range. Differentiation of such signal causes an amplification of undesired noise in both analog and digital circuits. This results in significant loss or disturbances in the useful data.
Technical Paper

Hill Start Assistance Developed for Buses Equipped with AMT

2016-04-05
2016-01-1111
The AMT (Automated Manual Transmission) has attracted increasing interest of automotive researches, because it has some advantages of both MT (Manual Transmission) and AT (Automatic Transmission), such as low cost, high efficiency, easy to use and good comfort. The hill-start assistance is an important feature of AMT. The vehicle will move backward, start with jerk, or cause engine stalling if failed on the slope road. For manual transmission, hill-start depends on the driver's skills to coordinate with the brake, clutch and throttle pedal to achieve a smooth start. However, with the AMT, clutch pedal is removed and therefore, driver can’t perceive the clutch position, making it difficult to hill-start with AMT without hill-start control strategy. This paper discussed about the hill start control strategy and its functioning.
Technical Paper

Methodology Development to Accurately Predict Aerodynamic Drag and Lift for Passenger Vehicles Using CFD.

2016-04-05
2016-01-1600
Important vehicle performance parameters such as, fuel economy and high speed stability are directly influenced by its aerodynamic drag and lift. Wind tunnel testing to asses these parameters requires heavy investment especially when test wind tunnel is not available in the country where vehicle development center is present. Hence to save cost and to compress development time, it is essential to asses and optimize parameters of a vehicle in very early stages of development. Using numerical flow simulations optimization runs can be carried out digitally. Industry demands prediction of aerodynamic drag and lift coefficients (CD,CL) within an accuracy of a few counts, consuming minimal HPC resources and in a short turnaround time. Different OEMs deploy different testing methods and different softwares for numerical simulations.
Journal Article

Body Induced Boom Noise Control by Hybrid Integrated Approach for a Passenger Car

2013-05-13
2013-01-1920
Vehicle incab booming perception, a low frequency response of the structure to the various excitations presents a challenging task for the NVH engineers. The excitation to the structure causing boom can either be power train induced, depending upon the number of cylinders or the road inputs, while transfer paths for the excitation is mainly through the power train mounts or the suspension attachments to the body. The body responds to those input excitations by virtue of the dynamic behavior mainly governed by its modal characteristics. This paper explains in detail an integrated approach, of both experimental and numerical techniques devised to investigate the mechanism for boom noise generation. It is therefore important, to understand the modal behavior of the structure. The modal characteristics from the structural modal test enable to locate the natural frequencies and mode shapes of the body, which are likely to get excited due to the operating excitations.
Technical Paper

Spot Weld Failure Prediction in Safety Simulations Using MAT-240 Material Model in LS-DYNA

2015-01-14
2015-26-0165
Spot welding is the primary joining method used in automobiles. Spot-weld plays a major role to maintain vehicle structural integrity during impact tests. Robust spot weld failure definitions is critical for accurate predictions of structural performance in safety simulations. Spot welds have a complex metallurgical structure, mainly consisting of fusion and heat affected zones. For accurate material property definitions in simulation models, huge number of inputs from test data is required. Multiple tests, using different spot weld joinery configurations, have to be conducted. In order to accurately represent the spot-weld behavior in CAE, detailed modeling is required using fine mesh. The current challenge in spot-weld failure assessment is developing a methodology having a better trade-off between prediction accuracy, testing efforts and computation time. In view of the above, cohesive zone models have been found to be very effective and accurate.
Technical Paper

Approach to Control the in Cab Noise without Affecting Passenger Comfort in AC Midi Buses

2015-01-14
2015-26-0125
This paper discusses various fruitful iterations / experiments performed to reduce air flow induced noise without compromising on total air flow requirement for thermal comfort and ways to avoid heat ingress inside the bus. Also the paper discusses the devised process for noise reduction through front loading of computer aided engineering and computational fluid dynamics analysis. Air conditioning buses in light commercial vehicle (LCV) segment is growing market in India, especially for applications like staff pick-up and drop, school applications and private fleet owners. The air-conditioning system is typically mounted on bus roof top and located laterally and longitudinally at center. It is an easiest and most feasible way to package air conditioning system to cater the large passenger space (32 to 40 seats) with the conditioned air. This makes air conditioning duct design simple and commercially viable.
Technical Paper

Energy Efficient Air Conditioned Buses

2015-01-14
2015-26-0044
This paper focuses on factors that enhance energy efficiency of air conditioning system on mid-sized, standard and premium buses with engine power from 125 to 280 HP. It covers aspects like light weighting of roof air conditioning system, usage of optimized ducting system with minimal resistance to blowers, deployment of rotary scroll compressor with fast idle control in place of reciprocating piston compressor. The scope of this paper covers AC compressors driven by main engine of vehicle/ bus, study related to auxiliary/donkey engine driven AC compressor is not considered. Context- In order to enhance fuel efficiency in buses an energy efficient air conditioning system should be deployed. This will lead to reduced parasitic load on the engine and translate into direct fuel saving.
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