Refine Your Search

Topic

Search Results

Viewing 1 to 20 of 20
Technical Paper

Analytical Estimation of Clutch Life for Manual Transmission

2019-04-02
2019-01-0335
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.
Technical Paper

Designing In-Cab Sound of Vehicles as per the Customer Driving Pattern on Roads

2019-01-09
2019-26-0170
Vehicle refinement from point of view reduction in its Noise, Vibrations and Harshness (NVH) affects customer’s buying decision and it also directly influences his/her driving experience on road at different speeds. Customer voice, however, indicates that a traditional process of developing design solutions is not aligned with the customers’ expectations. Traditionally the load cases for NVH development are focused only on quietness of passengers’ cabin at idling and in 3rd gear wide open throttle cruising on smooth roads. In reality, the Driver of a premium sedan car or a Sports Utility Vehicle (SUV) or a Compact Utility Vehicle (CUV) expects something different than merely the low sound pressure level inside the cabin. His/her driving pattern over a day plays a crucial role. A vehicle-owner wishes to balance various attributes of the in-cab sound and tactile vibrations at a time.
Technical Paper

Full Vehicle NVH CAE Methodology Development to Address Tailgate Rattling on a Future Tata SUV

2019-01-09
2019-26-0213
In recent years, car manufacturers have been working intensively on new ways to improve the quality of interior trims. Elimination of squeak and rattle has become one of the main concerns for car manufacturers lately, given the significance of these incidences in customers' perception of overall quality. Traditionally, rattle problems are found and fixed with physical tests at the late design stage, mainly due to lack of up-front CAE simulation prediction methodology and tools availability. This article presents a finite element based methodology for the improvement of rattle performance of a vehicle tailgate. In this study, appropriate finite element (FE) modeling technique was introduced to accurately predict occurrence of tailgate rattle. Simulation process using commercial software “Nastran” employing modal and forced frequency response analyses was illustrated. Design modifications were incorporated for performance improvement of rattling on present and future SUVs.
Technical Paper

Investigation of Cabin Noise while Accelerating on Low Mu Track through Simulation Approach Using Full Vehicle ADAMS/Car Model

2019-01-09
2019-26-0179
Cabin noise is a significant product quality criteria which enables the customers for product differentiation. There are various sources of cabin noise such as wind, structures(panels), engine, suspension, tire and roads. During product development phase, extensive tests has been conducted to improve vehicle dynamics behavior on various climatic conditions. One such test is accelerating vehicle on low mu or icy surface. While performing acceleration manoeuvre (tractions) on a low mu tracks, Cabin noise with source identified from front underbody & low tractive torque build up is reported. This undesirable behavior may occur due to following reason (1) Excitation of coupled modes between suspension and powertrain which induces torque fluctuation. (2) Transmissibility of various subsystem can be the reason for above problem statement. (3) Poorly chosen tire compounds and design leads to fluctuation in torque.
Technical Paper

Evaluation of the Tire Wear Possibility due to Non-Steerable Twin Tire Lift Axle on Heavy Commercial Vehicle

2019-01-09
2019-26-0066
The commercial vehicle market in India is shifting to higher payload capacity vehicles due to a lower transportation cost per unit goods. To cater this requirement, the vehicle manufacturers are designing the heavy multi-axle commercial vehicles and with higher per axle loading capacity. One of such a vehicle design involves five-axle vehicle with non-steerable, twin tire, lift axle. Though using a twin tires have increased loading capacity of lift axle compared to a single tire self-steerable lift axle, it can cause tire scrub while vehicle is turning and leads to a significant tire wear. The tire wear possibility due to use of non-steerable lift axle is estimated through simulation using full vehicle model in ADAMS. The operating zone of the vehicle, where maximum tire wear can occur, is identified through simulation. Different alternatives to reduce tire wear for this scenario are also discussed.
Technical Paper

Air Intake System Optimization for Passenger Car Engine

2019-01-09
2019-26-0044
The customer expectations in the passenger car market are predominantly in the areas of engine/vehicle performance along with NVH refinement. In addition, continuously evolving regulatory emission and crash norms with system cost considerations bring out multiple challenges on to design engineers. One of the vehicle systems that has its footprints on all of the above requirements is the engine air intake system. In this paper, using multidisciplinary approach we discuss the impact of air intake system design of a 3-cylinder gasoline engine on different attributes of customer requirements. The primary function of the air intake system is to provide filtered air to the engine. However, this paper explains how requirements like engine performance, NVH refinement, regulatory and styling, durability, servicing and system cost are affected by intake system design parameters.
Technical Paper

CAE Based Head Form Impact Simulations for Development of Vehicle Interiors

2019-01-09
2019-26-0237
The interior components of a passenger vehicle are designed to provide comfort and safety to its occupants. In the event of accident, vehicle interiors are primary source of injuries when occupants interact with them. Vehicle interiors consists of Instrument panel (IP), center console, seats and controls in front of seating position etc. Severity of the injuries depends on the energy dissipating characteristics, profiles, projections of different interior components. These are assessed by ECE R21 and IS12553 head form impact tests. To evaluate the Head form impact performance on Interior components, Computer Aided Engineering (CAE) simulations are extensively used during the vehicle development. In order to predict failure of plastic components and snap joints which might lead to expose sharp edges, it is critical to model plastic material and snap joint.
Technical Paper

Development and Prediction of Vehicle Drag Coefficient Using OpenFoam CFD Tool

2019-01-09
2019-26-0235
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 are 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 significant impact on product development cost when numbers of aerodynamic simulations expand.
Journal Article

Gearshift Quality Sensitivity Analysis

2019-01-09
2019-26-0328
Gearshift quality is a perceived quality parameter. Hence, is getting much importance because of the increased awareness about comfortable and refined driving experience, especially in the case of passenger cars. When the topic of gearshift feeling is broached in manual transmission vehicles, synchronizer pack (shifter sleeve, engaging gear, strut, synchronizer and gear synchro ring assembly) have been the focus point for optimization. Synchronizer type (single, double or triple cone), lining material, datch chamfer angle of shifter sleeve/synchro ring of gear/synchronizer, all of these have been extensively studied in the past to improve the gearshift quality. With stringent timelines for vehicle development, OEMs prefer to use off-the-shelf powertrain systems developed by powertrain manufacturers. Due to this, avenues to refine gearshift feel gets reduced to a large extent and hence refinement becomes difficult.
Technical Paper

Body Block FE Model Development and Correlation with Physical Tests

2017-01-10
2017-26-0293
Steering column and steering wheel are critical safety components in vehicle interior environment. Steering system needs to be designed to absorb occupant impact energy in the event of crash thereby reducing the risk of injury to the occupant. This is more critical for non-airbag vehicle versions. To evaluate the steering system performance, Body block impact test is defined in IS11939 standard [1]. Nowadays for product development, CAE is being extensively used to reduce development cycle time and minimize number of prototypes required for physical validation. In order to design the steering system to meet the Body Block performance requirements, a detailed FE model of Body Block impactor is required. The static stiffness and moment of inertia of body block are defined in SAE J244a [2]. The reference data available in SAE J244a is not sufficient to develop a Body Block model that would represent the physical impactor.
Technical Paper

Simulation of Heavy Commercial Vehicle Response to Rear Super Single Tire Blow Out

2017-01-10
2017-26-0341
The fuel economy of heavy commercial vehicles can be significantly improved by reducing the rolling resistance of tires. To reduce the rolling resistance of 6×4 tractor, the super single tires instead of rear dual wheel tires are tried. Though the field trials showed a significant increase in fuel economy by using super single tires, it posed a concern of road safety when these tires blowout during operation. Physical testing of tire blowout on vehicle is very unsafe, time consuming and expensive. Hence, a full vehicle simulation of super single tire blowout is carried out. The mechanical properties of tires such as cornering stiffness, radial stiffness and rolling resistance changes during the tire blowout; this change is incorporated in simulation using series of events that apply different gains to these mechanical properties.
Technical Paper

NVH Refinement of Small Gasoline Engine through Digital and Experimental Approach

2017-01-10
2017-26-0211
Today’s competitive market demands for low cost passenger cars with lighter, smaller size, peppy response and fuel efficient engines and having world class NVH refinement levels. For such requirements, it is essential to optimize the product starting from the design conceptual stage, considering all performance aspects. Generally, three cylinder engines, due to less reciprocating masses, compared to four-cylinder engine, are said to be fuel efficient for the same capacity. Nevertheless, NVH problems caused by inherent imbalance forces and couples remain as drawback of the three-cylinder engine. However, through optimal design of the crank train, control of cylinder to cylinder pressure variation, stiffening of the engine structure, optimizing the integration with a vehicle through proper design of mounts, NVH refinement levels can be improved.
Technical Paper

Tackle Low Frequency Structural Vibration in AMT Car using Gear Shift Schedule Optimization

2017-01-10
2017-26-0198
The present work focuses on optimization of gear shift pattern of an AMT vehicle to improve its NVH performance without causing any adverse effect on any other vehicle performance attribute. The vehicle which was identified with the structural body resonance at low frequency had discomforting boom noise in a particular engine rpm zone and at corresponding vehicle speed. With the initial shift pattern (will be referred as V1 gear shift schedule), the gear shifts were calibrated such that when vehicle is driven in the city with 20 to 60 kmph speed, the vehicle operated mostly in the best fuel economy zone but it used to pass through structural resonance frequency. This resulted in the presence of continuous boom leading to an unpleasant driving experience. In order to avoid the presence of boom noise during city driving, the gear shift points were optimized (will be referred as V2 gear shift schedule) such that the vehicle did not operate in affected engine speed range.
Journal Article

Performance Cascading from Vehicle-Level NVH to Component or Sub-System Level Design

2017-01-10
2017-26-0205
Before a physical proto-vehicle is assembled, various components or subsystems are ready by Tier-I or II suppliers. During final design judgement of the vehicle thru’ CAE or Mule-vehicle testing, performance target compliance need be assured for all these components to meet the Vehicle-level NVH targets. The work here studies some of the major components of a passenger car. Their individual NVH response can be critical to be cascaded for meeting the final targets for the vehicles running over roads. Conclusions of the study challenge some of traditional beliefs or generic targets. Often the component level response deviating from its own targets may not have an adverse influence on NVH of the vehicle facing multiple excitations from tyre/road, wind and power-train in a frequency band of interest.
Technical Paper

A Robust Solution for a Power-Train Mounting System for Automotive NVH Refinements

2015-01-14
2015-26-0140
Production variations of a heavy duty truck for its vibrations were measured and then analyzed through an Ishikawa diagram. Noise and Control factors of the truck idle shake were indentified. The major cause was found to be piece to piece variations of its power-train (PT) rubber mounts. To overcome the same, a new nominal level of the mount stiffness was sought based on minimization of a cost function related to vibration transmissibility and fatigue damage of the mounts under dynamic loadings. Physical prototypes of such mounts were proved to minimize the variations of the driver's seat shake at idling among various trucks of the same design. These learning's are useful for design of various subsystems or components to refine the full vehicle-Noise Vibration Harshness (NVH) at the robust design level.
Technical Paper

Crash Pulse Characterization for Restraints System Performance Optimization

2015-01-14
2015-26-0152
The vehicle crash signature (here on referred as crash pulse) significantly affects occupant restraints system performance in frontal crash events. Restraints system optimization is usually undertaken in later phase of product development. This leads to sub-optimal configurations and performance, as no opportunity exists to tune vehicle structure and occupant package layouts. In concept phase of development, crash pulse characterization helps to map occupant package environment with available structure crush space and stiffness. The crash pulse slope, peaks, average values at discrete time intervals, can be tuned considering library of restraints parameters. This would help to derive an optimal occupant kinematics and occupant-restraints interaction in crash event. A case study has been explained in this paper to highlight the methodology.
Technical Paper

Simulation of Clutch Inertial Effects on Gear Shifting, Synchronizer Capacity and Accelerated Testing of Synchronizers

2013-11-27
2013-01-2807
In today's scenario, most of the OEMs use manual transmissions with synchronizer gear shifting system for ease of gear shifting. It gives very high fuel efficiency. Gear shifting is a customer touch point, hence it is very important to select adequate synchronizer capacity so that it will perform in better and last longer. To test the synchronizers, there are many test methods which give the idea about life of synchronizer and its performance, in different conditions. Regular synchronizer rig tests consume lot of time in deriving the results. So it is very important to find out a way which will give same results within short time period. To carry out the short time test or accelerated test, we need to understand the effect of various factors like reflected inertia, drag torque, differential speed, synchronizing time, and gear shifting force on synchronizer capacity.
Technical Paper

Opportunities and Control Measures for Sustainable Transport Growth in Emerging Economy Regions-India

2013-04-08
2013-01-1037
Sustainable development is a very complex concept involving several inter-related issues and concerns. Globalization has given a new dimension to social, economic and environmental development associated with the perceived responsibilities and growth indicators. Both developing and developed countries have the opportunities to exploit comparative advantages in the changing economic, social and environmental scenario while targeting sustainable growth together with expansion of the business prospects. Every region perceives these opportunities with different notion. There is a plethora of indicators for assessing sustainability. However, assessment criteria, prioritization and trade off for a given sustainability parameter against the other could be very complex while evolving transport growth model in emerging economies.
Technical Paper

Investigation of Frequent Pinion Seal and Hub Seal Leakages on Heavy Commercial Vehicles

2010-10-05
2010-01-2015
The automotive sector is going through a phase of stiff competition among various Original Equipment Manufacturers for increasing their profitability while ensuring highest levels of customer satisfaction. The biggest challenge for such companies lies in minimizing their overall cost involving investments in Research and Development, manufacturing, after sales service and warranty costs. Higher warranty costs not only affect the net profit but in turn it also affects the brand image of the company to a large extent in the long run. An effort is made here to target such warranty costs due to frequent tail pinion and hub seal leakages on single reduction/hub reduction axles of Heavy Commercial Vehicles in the field. A preliminary study involving the severity analysis of such failures is followed by a step by step investigation of these failures.
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).
X