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Technical Paper

Design Strategies for Meeting ECE R14 Safety Test for Light Commercial Vehicle

2010-10-05
2010-01-2017
The ECE R-14, AIS015 safety standard specifies the requirements of the safety belt anchorages namely, minimum numbers, their locations, static strength to reduce the possibility of their failure during accidental crashes for effective occupant restraint and the test procedures. This standard applies to the anchorages of safety belts for adult occupants of forward facing or rearward facing seats in vehicles of categories M and N. ECE R14 ensures the passenger safety during sudden acceleration/retardation and accidents. Early simulations revealed some structural short falls that demanded cabin improvements in order to fulfill regulation requirements for the seal belt anchorage test. This paper describes the innovative design modifications done to meet the seat belt anchorage test. Good correlation with the test is achieved in terms of deformations. These simulation methods helped in reducing the number of intermediate physical tests during the design process.
Technical Paper

Functional Safety - Progressing Towards Safer Mobility

2013-11-27
2013-01-2841
Increasing complexity in E/E architecture poses several challenges in developing comfortable, clean and safe cars. This mandates robust processes to mitigate potential hazards due to malfunction of electronic systems throughout the product life cycle. With the advent of ISO 26262 [1] which provides guidelines for developing safe cars, the process is getting standardized towards safer mobility. In this paper, the functional safety process is briefly covered and a case study of Hazard Analysis and Risk Assessment for specific E/E system is presented. An in-house tool developed for functional safety process and management is covered.
Technical Paper

Effects of Governing Parameters on the Performance and Emissions of Hydrogen Engine for Automotive Application

2013-11-27
2013-01-2891
This report describes work performed jointly by Mahindra & Mahindra and IIT Delhi, including both simulations and single-cylinder engine development for three wheeler application, to quantify the effects of various parameters on the performance and NOx emission of an internal combustion engine fuelled by hydrogen. AVL Boost software was used to simulate the experimental conditions, by using Vibe 2-Zone combustion and Woschni heat models, together with kinetic equations for emission calculations. Developed AVL Boost Model was validated against the test result from a modified single cylinder CNG engine for three wheeler application fuelled with Hydrogen by comparing the performance and NOx emission at the same operating conditions. A good agreement was obtained between the results of the Boost Model and Experimental results.
Technical Paper

A Development of Booming Index of Diesel SUV by using Artificial Neural Network

2012-06-13
2012-01-1542
In today's competitive scenario, understanding mental modal map of individual customer perception plays a major role to create the brand image of vehicle. Among them “comfortable sound” is one of the important criteria for customer satisfaction, especially in case of diesel vehicle, where in-cab sound quality plays a crucial factor. Often customer perception concerning comfort in automotive industry relies on subjective comfort evaluation method. Converting the customer perception into objective measurements and to correlate them is often tough task for NVH engineers. It is because of human sensation behavior differs from persons to person, mental map, geographical location and domain knowledge. In addition acoustic & comfort relevant aspects are often subjectively evaluated based on jury trials conducted on the prototype vehicle and class competitive benchmark vehicles to get the feel & confidence of product for different gateways.
Technical Paper

Servomotor Controlled Standard Automated Manual Transmission for Rapid Smooth Shifts

2012-09-24
2012-01-1989
Present day AMT unit uses two high pressure hydraulically operated pistons for select & shift operations which make the unit weigh around 8kg. Besides this it also makes the unit more complex & unreliable with a lot of torque interruption. The use of electrical servo motors steps in here as a better alternative as it provides a more precise and smoother shift. To test this we used a 5 Gear-Manual Transmission. For the selection, a precise 14.5 degree of twisting was required which was easily achieved by the servo motor. Further, shift of 10.5mm could be made possible by using the motor to shift the rack using a pinion on the shaft. This system then essentially eliminates the whole hydraulic circuit, the housing of actuator pack & power pack making it a simpler unit all together. A Motor is attached to the output shaft of the Transmission which drives in power while the AMT unit is making transition from one gear to another.
Technical Paper

Powertrain Noise & Sound Quality Refinement for New Generation Common Rail Engines

2010-06-09
2010-01-1414
Noise & sound quality has gained equal importance as that of emissions and crash safety of the vehicles. With increased engine power to weight ratio, the challenges for NVH engineers has increased multifold. Passenger compartment comfort levels are getting affected largely due to lighter and powerful engines. Same time, there is pressure to reduce overall vehicle weight and cost. This impose constraints to NVH engineer in designing the body structure and sound package to reduce the effect of powertrain forces and airborne noise on passenger compartment. In addition to weight constraints, there is trend emerging to use two & three cylinder engines which need to perform on par with four cylinder engines. This has shown adverse effect on vehicle NVH performance due to wider low frequency unbalance forces.
Technical Paper

Turbocharging a Small Two Cylinder DI Diesel Engine - Experiences in Improving the Power, Low End Torque and Specific Fuel Consumption

2011-09-11
2011-24-0133
Turbocharged common rail direct injection engines offer multiple benefits compared to their naturally aspirated counterparts by allowing for a significant increase in the power and torque output, while simultaneously improving the specific fuel consumption and smoke. They also make it possible for the engine to operate at a leaner air/fuel mixture ratio, thereby reducing particulate matter emission and permitting higher EGR flow rates. In the present work, a two cylinder, naturally aspirated common rail injected engine for use on a load carrier platform has been fitted with a turbocharger for improving the power and torque output, so that the engine can be used in a vehicle with a higher kerb weight. The basic architecture and hardware remain unchanged between the naturally aspirated and turbocharged versions. A fixed geometry, waste gated turbocharger with intercooling is used.
Technical Paper

Hybrid Oil Sump for CI Engine

2011-09-11
2011-24-0135
Recently fuel economy and stringent emission norms are the ever growing concern in automotive global scenario. So, automotive engineers are constantly seeking new cost effective methodologies and techniques to achieve considerable weight reduction and improved performance. Nowadays Automotive OEMs are using Aluminum Oil sump (which is a structured part of an engine and supports considerable amount of transmission housing weight) for better emission, reducing the engine height, engine weight and NVH levels. Our present work reveals the concept of ‘Hybrid oil sump’ which made by sheet metal and aluminum in such a way that weight and cost reduced by 20% and 30 % respectively, without compromising NVH and strength properties. Exactly it deals the iteration part of design to arrive the optimum model, various structural modifications since it carries considerable amount of weight of transmission.
Technical Paper

A Systematic Approach for Weight Reduction of BIW Panels through Optimization

2010-04-12
2010-01-0389
This paper describes application of Design of Experiments (DOE) technique and optimization for mass reduction of a Sports utility vehicle (SUV) body in white (BIW). Thickness of the body panels is taken as design variable for the study. The BIW global torsion, bending and front end modes are key indicators of the stiffness and mass of the structure. By considering the global modes the structural strength of the vehicle also gets accounted, since the vehicle is subjected to bending and twisting moments during proving ground test. The DOE is setup in a virtual environment and the results for different configurations are obtained through simulations. The results obtained from the DOE exercise are used to check the sensitivity of the panels. The panels are selected for mass reduction based on the analysis of the results. This final configuration is further evaluated for determining the stiffness and strength of the BIW.
Technical Paper

Correlation of Test with CAE of Dynamic Strains on Transmission Housing for 4WD Automotive Powertrain

2010-04-12
2010-01-0497
Reducing the vibrations in the powertrain is one of the prime necessities in today's automobiles from NVH and strength perspectives. The necessity of 4×4 powertrain is increasing for better control on normal road and off-road vehicles. This leads to bulky powertrains. The vehicle speeds are increasing, that requires engines to run at higher speeds. Also to save on material costs and improve on fuel economy there is a need for optimizing the mass of the engine/vehicle. The reduced stiffness and higher speeds lead to increased noise and vibrations. One more challenge a powertrain design engineer has to face during design of its transmission housings is the bending / torsional mode vibrations of powertrain assembly. This aggravates other concerns such as shift lever vibrations, shift lever rattle, rise in in-cab noise, generation of boom noise at certain speeds, etc. Hence, reducing vibrations becomes an important and difficult aspect in design of an automobile.
Technical Paper

Emission Optimization Approach to Meet the Current Indian Emission Norm Without EGR Cooling for a Vehicle Equipped with Common Rail Diesel Engine

2014-03-24
2014-01-2022
In India, diesel engine powered vehicles are finding rising demand due to the subsidy offered on diesel. Currently, BS-IV emission norm (equivalent to E-IV in Europe) is in existence. To meet this emission norm, OEM look for improved engine design, use of common rail injection system, advanced after treatment. In the current article, a methodology is demonstrated by which the required emissions on multipurpose vehicle (MPV) powered with 2.2L common rail injection system was met with no need of EGR cooling. This was achieved by identifying the operating points from the BS-IV emission cycle where EGR cooling is beneficial. The next step involves assessing the loss of function due to its removal. The final step involves strategies which can bring the original optimized value of NOx-PM. Removal of EGR cooling avoids the cooling of intake charge and reduces the HC and CO emission. Also, it gets rid of complication in the under bonnet packaging and leads to maintenance free operation.
Technical Paper

Monocoque Vehicle Body-In-White Life Evaluation Using Torsion Endurance Test on Rig

2016-04-05
2016-01-0276
In an automotive product development environment, identifying the premature structural failures is one of the important tasks for Body-In-White (BIW), sub-assemblies and components. The integrated car body structure i.e. monocoque structure, is widely used in passenger cars and SUVs. This structure is subjected to bending and torsional vibrations, due to dynamic loads. Normally the stresses due to bending are relatively small compared to stresses due to torsion in Body-In-White under actual road conditions [1]. This paper focuses on evaluating the life of Body-In-White structures subjected to torsional loading. An accelerated test method was evolved for identifying failure modes of monocoque BIW by applying torsion fatigue. The observation of the crack generation and propagation was made with respect to a number of torsion fatigue cycles.
Technical Paper

Improved Powertrain Mounts Position for Four Cylinder Engine Commercial Vehicle with Four Point Mounting Configuration

2016-02-01
2016-28-0231
In this era of engine downsizing, the powertrains with higher power densities are configured on next generation vehicles. The bare four cylinder engine without balancer shaft has higher surface velocities, sound pressure & power levels and nearly 10 to 15% higher base level vibration/forces over older generations. Adapting such engines on a new vehicle platform with stringent NVH targets is challenging. Powertrain mount modal analysis, 6DOF or 16DOF is a primary tool followed for initial mount positioning and stiffness definition. From our earlier experiences we have the knowledge that most of the 6DOF iterations lead to the mount positions which are less feasible as per vehicle architecture and packaging point of view, and further optimization is needed to arrive at suitable mount position through 6DOF analysis. In a drive to have first time right solution with minimal modifications, the study was conducted to understand the role of mount position & isolation on different vehicles.
Technical Paper

Silent Block Bush Design and Optimization for Pick-Up Truck Leaf Spring

2017-03-28
2017-01-0455
Structural elastomer components like bushes, engine mounts are required to meet stringent and contrasting requirements of being soft for better NVH and also be durable at different loading conditions and different road conditions. Silent block bushes are such components where the loading in radial direction of bushes are high to ensure the durability of bushes at high loads, but has to be soft on torsion to ensure good NVH. These requirements present with unique challenge to optimize the leaf spring bush design, stiffness and material characteristics of the rubber. Traditionally, bushes with varying degree of stiffness are selected, manufactured and tested on vehicle and the best one is chosen depending on the requirements. However, this approach is costly, time consuming and iterative. In this study, the stiffness targets required for the bush were analysed using static and dynamic load cases using virtual simulation (MSC.ADAMS).
Technical Paper

Prediction of Hub Load on Power Steering Pump Using Dynamic Simulation and Experimental Measurement

2017-03-28
2017-01-0416
New trend in steering system such as EPS is coming up, but still hydraulic power steering system is more prevalent in today’s vehicles. Power steering pump is a vital component of hydraulic power steering system. Failure of steering pump can lead to loss of power assistance. Prediction of hub load on pump shaft is an important design input for pump manufacturer. Higher hub loads than the actual designed load of pump bearing may lead to seizure of pump. Pump manufacturer has safe limits for hub load. Simulations can assist for optimization of belt layout and placement of accessories to reduce the hub load. Lower hub load can have direct effect on improvement of pump durability. This paper deals with dynamic simulation of belt drive system in MSC.ADAMS as well as vehicle level measurement of hub load on power steering pump.
Technical Paper

Development of a Standalone Application in MATLAB to Generate Brake Performance Data

2019-04-02
2019-01-0513
Predicting the brake performance and characteristics is a crucial task in the vehicle development activity. Performance prediction is a challenge because of the involvement of various parts in the brake assembly like booster, master cylinder, calipers, disc and drum brakes. Determination of these characteristics through vehicle level tests requires a lot of time and money. This performance prediction is achieved by theoretical calculations involving vehicle dynamics. The final output must satisfy the regulations. This project involves the creation of a standalone application using MATLAB to predict the various brake performances such as: booster characteristics, adhesion curves, deceleration and pedal effort curves, behavior of brakes during brake and booster failed conditions and braking force diagrams based on the given user inputs. Previously, MS Excel and an application developed in the TK Solver environment was used to predict the brake performance curves.
Journal Article

Acoustic Analysis of a Compact Muffler for Automotive Application

2017-06-17
2017-01-9550
A production muffler of a 2.2 liter compression ignition engine is analyzed using plane wave (Transfer Matrix) method. The objective is to show the usefulness of plane wave models to analyze the acoustic performance (Transmission Loss, TL) of a compact hybrid muffler (made up of reactive and dissipative elements). The muffler consists of three chambers, two of which are acoustically short in the axial direction. The chambers are separated by an impervious baffle on the upstream side and a perforated plate on the downstream side. The first chamber is a Concentric Tube Resonator (CTR). The second chamber consists of an extended inlet and a flow reversal 180-degree curved outlet duct. The acoustic cavity in the third chamber is coupled with the second chamber through the acoustic impedances of the end plate and the perforated plate.
Technical Paper

Optimization of Piston Skirt Profile Design to Eliminate Scuffing and Seizure in a Water Cooled Gasoline Engine

2015-04-14
2015-01-1726
Piston is a critical component of the engine as it exposed to high inertial and thermal loads. With the advent of high performance engines, the requirement of the piston to perform in extreme conditions have become quintessential. Piston scuffing is a common engine problem where there is a significant material loss at the piston and the liner, which could drastically affect the performance and the longevity of the components. This detrimental phenomenon would occur if the piston is not properly designed taking into consideration the thermal and structural intricacies of the engine. A water-cooled gasoline engine which had significant wear pattern on its piston skirt and liner was considered for this study. The engine block was made of aluminum alloy with a cast iron sleeve acting as liner. The piston-liner system was simulated through a commercially available numerical code which could capture the piston's primary and secondary motion.
Technical Paper

Analysis and Elimination of Howling Noise in Compact Utility Vehicle

2017-07-10
2017-28-1922
NVH is becoming one of the major factor for customer selection of vehicle along with parameters like fuel economy and drivability. One of the major NVH challenges is to have a vehicle with aggressive drivability and at the same time with acceptable noise and vibration levels. This paper focuses on the compact utility vehicle where the howling noise is occurring at higher rpm of the engine. The vehicle is powered by three cylinder turbocharged diesel engine. The noise levels were higher above 2500 rpm due to the presence of structural resonance. Operational deflection shapes (ODS) and Transfer path analysis (TPA) analysis was done on entire vehicle and powertrain to find out the major reason for howling noise at higher engine rpm. It is observed that the major contribution for noise at higher rpm is due to modal coupling between powertrain, half shaft and vehicle sub frame.
Technical Paper

Vehicle Sway Prediction in Hydraulic Circuit Failed Condition on 4 Wheeled Vehicle with ‘X’ Split Brake Configuration

2017-01-10
2017-26-0344
A 4 wheeled vehicle with X-split brake configuration, in hydraulic circuit failed condition will have a behavior of induced sway due to braking force variation in the front and rear diagonally. With increasing vehicle speed, engine power & customer expectations, the situation becomes more critical and challenging in designing a brake system which caters in meeting the homologation requirement at an expense of vehicle sway within controllable limits of driver / customer. This paper proposes a novel approach & methodology to overcome the above situation by predicting the effect of brake force distribution variation on the vehicle swaying behavior during circuit failed braking condition. This study will quantify vehicle sway, caused due to imbalance in brake force distribution during a circuit failed braking event on X Split configuration vehicles.
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