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Technical Paper

Supervisory Control Strategy for Mild Hybrid System - A Model Based Approach

2013-04-08
2013-01-0503
In this paper, a mild hybrid system is studied for Indian drive conditions. The study is focused to first come up with detailed component sizing through simulation. Different features of mild hybrid system are studied for their individual and cumulative contribution in the fuel economy improvement over the base non-hybrid vehicle. Model based development approach has been employed to develop a supervisory control strategy for such a system. Model based design saves time and cost as it gives flexibility to the control engineer to validate the control design at an early stage of development. The supervisory control strategy is first tested in a simulated environment and then, on a vehicle. To prove the system function, a full hybrid vehicle is experimented as a mild hybrid configuration. Experiments are conducted on the test vehicle over MIDC (certification cycle) to understand the impact of mild hybridization on fuel economy and tail pipe emissions
Technical Paper

Dynamic Simulation of Shift Tower

2013-11-27
2013-01-2790
Manual transmission is one of the key system of power-train to which driver directly interacts, so its shift feeling is important for the merchantability. The importance of the gear shift quality of manual transmissions has increased significantly over the past few years as the refinement of other vehicle systems has increased and also due to rise in customer expectations. Shift Tower is a system to assist the driver during selecting and shifting of Gears. The dynamic interaction of shift Tower at a component level is difficult to interpret by traditional test methods and virtually impossible at concept stage. To overcome these difficulties a dynamic model of the entire Shift Tower mechanism i.e. Shift select lever, 3D Ramp, Detent Pin, Spring, Interlock mechanism has been created. The model predicts the gearshift quality i.e. Shift and Select force values for a given set of input parameters, which can be correlated against test data.
Technical Paper

Improving Side Crash Performance of a Compact Car via CAE

2014-04-01
2014-01-0546
The side impact accident is one of the very severe crash modes for the struck side occupants. According to NHTSA fatality reports, side impact accounts for over 25% of the fatalities in the US. Similar fatality estimates have been reported in the EU region. Side crash compliance of a compact car is more severe because of the less space available between the occupant and the vehicle structure, stringent fuel economy, weight and cost targets. The current work focuses on the development of Side body structure of a compact car through Computer Aided Tools (CAE), for meeting the Side crash requirements as per ECE R95 Regulation. A modified design philosophy has been adopted for controlling the intrusion of upper and lower portion of B-pillar in order to mitigate the injury to Euro SIDII dummy. At first, initial CAE evaluation of baseline vehicle was conducted.
Technical Paper

Improving Offset Crash Performance and Injury Mitigation via Multi-Body Simulation and Structural CAE

2014-04-01
2014-01-0939
Recent advancement in numerical solutions and advanced computational power has given a new dimension to the design and development of new products. The current paper focuses on the details of work done in order to improve the vehicle performance in Offset deformable Barrier (ODB) crash as per ECER-94. A Hybrid approach involving the Structural Crash CAE as well as Multi-body Simulation in MADYMO has been adopted. In first phase of the development, CAE results of Structural deformation as well as Occupant injury of the baseline model were correlated with physical test data. The second phase includes the improvement in intrusion and crash energy absorption by structural countermeasures in the vehicle body. In third phase parametric study has been carried out via Madymo simulation in order to decide on the factors which can be controlled in order to mitigate the Occupant injury. Recommendations of Madymo simulation have been confirmed by conducting Physical sled tests.
Technical Paper

Optimal Torque Handling in Hybrid Powertrain for Fuel Economy Improvement

2013-01-09
2013-26-0068
In this work, a parallel full Hybrid Electric Vehicle (HEV) was optimized to further lower its carbon footprint without opting for any additional hardware change. The study was focused to first recognize the system efficiency of the HEV and identify its low efficiency points over the MIDC. Thereafter, different functions of the HEV were studied for their individual and cumulative contribution in the fuel economy improvement over the base non-hybrid vehicle. This, along with the low system efficiency points helped in identifying the potential areas for improvement in fuel economy. With changes in calibration and control strategies resulting in an optimal torque handling between the E-machine and the ICE, it was established through simulation and subsequent experiments conducted on chassis dynamometer, that the fuel economy of the HEV tested can be improved with the performance remaining unchanged and emissions meeting regulatory requirements.
Technical Paper

Passenger Car Front Air - Dam Design Based on Aerodynamic and Fuel Economy Simulations

2013-01-09
2013-26-0063
Computational Fluid Dynamics (CFD) is used extensively in the optimization of modern passenger car to meet the ever growing need of higher fuel economy, better engine and underbody cooling. One of the way to achieve better fuel economy is to reduce the vehicle overall resistance to flow, know as drag. Vehicle drag is a complex phenomenon governed by vehicle styling, component shape, layout and driving velocity and road conditions. To reduce the drag a lot of aero-parts are used these days such as air-dam, skirts, spoiler, undercover, dams etc. However the design of these aero-parts must be optimized to get the desired result as their addition alone does not guarantee improvement in performance. This paper aims at studying the effect of air-dam height and position on vehicle aerodynamics. Also the effect of air-dam addition was verified using fuel economy simulations.
Technical Paper

An Alternate Methodology to Measure the A-Pillar Obstruction in Passenger Cars

2013-01-09
2013-26-0030
With ever increasing demand for vehicle safety and fuel efficiency, Body in White (BIW) designers are striving for vehicle's body mass optimization leading to the development of lean designs. Nevertheless, considerations like ergonomics also play a significant role while deciding the vehicle structure. As an example, A-pillar (front pillar) plays a major role in vehicle's passive safety. Increase in its cross section size, beyond a particular grade and gauge optimization is eminent to meet target requirements of rigidity and crash. However, the increased obstruction because of the wider section would not only lead to poor visibility and a claustrophobic feeling to the driver but also lead to a lesser response time for him or her to prevent a collision. Obstruction from A-pillar can be a subjective feeling of driver but it should also be quantified and measured to optimize the A-pillar structure. Numerous methodologies are being adopted globally to measure the A-pillar obstruction.
Technical Paper

A Study on the Idle Combustion Stability of a CNG Powered Naturally Aspirated Engine

2013-01-09
2013-26-0003
In view of rising oil prices and concern for the greenhouse gas emissions, the need for greener and efficient engines is increasing. Thus, automobile manufacturers are trying to improve the performance and efficiency of the engine while keeping compliance with the stringent emission norms. CNG, with its high H/C ratio, makes it a clean fuel by significantly reducing the emission of green-house gas carbon-dioxide. CNG, being cheap compared to other conventional fuels, is an added advantage and hence is gaining popularity. Along with improvement in the part load and full load efficiency, Engine manufactures are looking to lower the idle speed for better fuel economy. Lowering the idle speed has to be optimized as, it reduces the combustion stability of the engine which in turn increases the variation of Indicated Mean Effective Pressure (IMEP) resulting in high structural vibration from the engine and to vehicle body.
Technical Paper

Application and Development Challenges of Dynamic Damper in Cabin Booming Noise Elimination

2014-04-01
2014-01-0013
Automotive OEMs quest for vehicle body light weighting, increase in Fuel efficiency along with significant cut in the emissions pose significant challenges. Apart from the effect on vehicle handling, the reduction of vehicle weight also results in additional general requirements for acoustic measures as it is an important aspect that contributes to the comfort and the sound quality image of the vehicle, thus posing a unique challenge to body designers and NVH experts. Due to these conflicting objectives, accurate identification along with knowledge of the transfer paths of vibrations and noise in the vehicle is needed to facilitate measures for booming noise dampening and vehicle structure vibration amplitude. This paper focuses on the application of a unique design and development of vehicle body structure anti-vibration dynamic damper (DD), unique in its aspect in controlling booming noise generated at a specific RPM range.
Technical Paper

Vehicular Cabin Noise Source Identification and Optimization Using Beamforming and Acoustical Holography

2014-04-01
2014-01-0004
The automobile market is witnessing a different trend altogether - the trend of shifting preference from powerful to fuel efficient machines. Certain factors like growing prices of fuel, struggling global economy, environmental sensitiveness and affordability have pushed the focus on smaller, efficient and cleaner automobiles. To meet such requirements, the automobile manufacturers, are going stringent on vehicle weights. Using electric and hybrid power-plants are other options to meet higher fuel efficiency and emission requirements but significant cost of these technologies have kept their growth restricted to only few makers and to only few regions of the globe. Optimizing the vehicle weight is a more attractive option for makers as it promises lesser time to market, is low on investment and allows use of existing platforms.
Journal Article

Influence of Low Viscosity Lubricating Oils on Fuel Economy and Durability of Passenger Car Diesel Engine

2012-01-09
2012-28-0010
Continuously rising fuel prices and global concern on climate change have resulted in a need to deliver vehicles with increased fuel economy. This has to be achieved without compromising on performance, durability and cost. Passenger car manufacturers are looking at various ways to maximize fuel economy. Major part of fuel saving can be tapped from engine itself. This can be done by activities on engine as below: Improving overall combustion efficiency and hence BSFC Efficient thermal management. Weight reduction of engine parts or complete downsizing Hybridization. Reducing engine losses i.e. parasitic losses from auxiliaries and frictional losses. This paper is focused on the reduction of engine frictional losses (FMEP) through the use of low viscosity lubrication oils. Various factors in lubrication oil contribute to friction. Experimental approach to quantifying the effect of different parameters of lubrication oil on total engine friction is presented.
Technical Paper

Development of Bi-fuel CNG Engine based passenger vehicle and Field Trials study in Indian condition

2009-12-13
2009-28-0019
Compressed natural gas (CNG) is being explored as a sustainable renewable fuel for vehicles in India due to mounting foreign exchange expenditure to import crude petroleum. Impending emissions regulations for diesel engines, specifically exhaust particulate emissions have caused engine manufacturers to once again examine the potential of alternative fuels. Much interest has centered on compressed natural gas (CNG) due to its potential for low particulate and hydrocarbon based emissions. Natural gas engine development projects have tended toward the use of current gasoline engine technology (stoichiometric mixtures, closed-loop fuel control and exhaust catalysts). Significant amount of research and development work is being undertaken in India to investigate various aspects of CNG utilization in different types of engines. This paper discusses about the development of the bi-fuel CNG engine for passenger vehicular application.
Technical Paper

Effect of PVC Skin and Its Properties on Automotive Door Trim Inserts

2017-03-28
2017-01-0492
Plastic plays a major role in automotive interiors. Till now most of the Indian automobile industries are using plastics mainly to cover the bare sheet metal panels and to reduce the weight of the vehicle along with safety concerns. Eventually Indian customer requirement is changing towards luxury vehicles. Premium look and luxury feel of the vehicle plays an equal role along with fuel economy and cost. Interior cabin is the place where aesthetics and comfort is the key to attract customers. Door Trims are one of the major areas of interiors where one can be able to provide premium feeling to the customer by giving PVC skin and decorative inserts. This paper deals with different types of PVC skins and its properties based on process constraints, complexity of the inserts. Door trim inserts can be manufactured by various methods like adhesive pasting, thermo-compression molding and low pressure injection molding process etc.
Technical Paper

A New Analytical Model for Clutch System Modeling and Design Optimization

2019-04-02
2019-01-0840
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
Technical Paper

Seat Belt Reminder Sensor Selection for Optimized Performance and Driver Convenience

2019-04-02
2019-01-0832
Use of safety belts inside a vehicle is necessary to ensure the safety of passengers as well as drivers. To promote the use of seat belts, a seatbelt reminder system is utilized. This system incorporates a sensor for checking seat occupancy for the passenger seat. Activation of these sensors depends on various parameters like seat pad shape, seat upholstery, vehicle H-point, a load on the seat, etc. In this study, the load factor on the seat is studied. The load on the seat may come from occupants or due to the objects placed on the seat. The detection of objects as an occupant may result in false seat belt reminder alarm and cause inconvenience to the customers. Subjective analysis and surveys, covering a broad range of market population, were done to identify such objects. Consequently, performance requirements were determined to facilitate sensor optimization and selection.
Technical Paper

Determining the Parameters of Feeling for a Mechanism of Seat Adjustment

2017-03-28
2017-01-1392
The seating system is an inseparable part of any automobile. Its main function is not only to provide a space to the user for driving but also to provide support, comfort and help to ergonomically access the various features and necessary operations of the vehicle. For comfort and accessibility, seats are provided with various mechanisms for adjustments in different directions. Typical mechanisms used for seating adjustment include seatback recliners, lifters (height adjusters), longitudinal adjusters, lumber support, rear seat folding mechanism etc. These mechanisms can be power operated or manual based on vehicle/market requirements. For manual mechanisms, the occupant adjusts the position of seat by operating the mechanism with his/her hand. Often comfort to the occupant during operation is limited to the operating effort of the mechanism. However, as will be shown through this study, operating effort is only one of the parameters which provide overall comfort feeling.
Technical Paper

Study and proposals for improving static comfort in automotive seating

2017-03-28
2017-01-1389
Automotive seating is designed by considering safety, comfort and aesthetics for the occupants. Seating comfort is one of the important parameters for the occupant for enhancing the overall experience in a vehicle. Seating comfort is categorized as static (or showroom) comfort and dynamic comfort. The requirements for achieving static and dynamic comfort can sometimes differ and may require design parameters such as PU hardness to be set in opposite directions. This paper presents a case wherein a base seat with good dynamic comfort is taken and an analysis is done to improve upon the static comfort, without compromising on the dynamic comfort. The study focuses on improving the initial comfort by considering various options for seating upholstery.
Technical Paper

Investigation on the Effect of Coolant Temperature on the Performance and Emissions of Naturally Aspirated Gasoline Engine

2011-01-19
2011-26-0089
Downsizing of engines is becoming more popular as manufacturers toil for increased fuel economy. Due to the downsizing of engines, Brake Mean Effective Pressure (BMEP) tends to increase, which in turn increases the heat release from engine. This necessitates the need for optimizing cooling system in order to get higher engine output and lower emissions to comply with stringent emission norms. In earlier engines, thermo-siphon principle was used with water as the coolant. This has been replaced in modern engines with pressurized cooling system with coolants like ethylene glycol mix. Along with the conventional objective of increased material durability with the optimized engine cooling system, it has been found that there is an improvement in the engine output due to increased charging efficiency. This paper describes the effect of engine coolant temperature on performance, emission and efficiency of a three-cylinder naturally aspirated spark ignited engine.
Technical Paper

Passenger under Foot Structure and its Efficacy:-Analytical & Experimental Evaluation

2018-04-03
2018-01-0154
Increasing customer expectations of comfort and convenience inside the vehicle has resulted in OEMs working on various solutions to improve interior ergonomics and overall layout. One of the key areas of focus has been the ease of ingress into and egress from the vehicle. But with increased sharing of platforms in OEM Model Lineup, due to obvious benefits like cost and common tooling/parts, it is very difficult to achieve improved results in different vehicles (like Hatchback, Notchback, SUV etc.) but with same underpinnings. One of the commonly used approaches is provision of false flooring via floor pads for front / Rear Passengers for easy Egress-Ingress. Floor Pads are used to maintain similar comfort levels across different vehicles sharing common platform and to maintain similar relationship between Foot resting positions and Side Sill.
Technical Paper

CAE Driven Improvement in Frontal Offset Crash Performance of a Compact Car

2014-04-01
2014-01-0375
Offset crash compliance of a compact car is severe due to the compact layout and stringent fuel economy, weight and cost targets. Scope of the current work is to improve the structural crash performance of a compact car through CAE, in order to meet the offset frontal crash requirements as per ECE R94 Regulation. The project has been classified in three main phases. First phase includes the evaluation of baseline vehicle in CAE. In order to ensure the accuracy of CAE prediction, a methodology for predicting Spotweld rupture was implemented. Using this methodology, it is possible to find out the location and time of spotweld rupture as well as propagation of spotweld rupture in CAE. CAE results of spotweld rupture prediction showed good agreement with the physical test. In second phase, design iterations were carried out in order to meet the performance targets of structural deformation.
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