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Technical Paper

Design of Front Structure of Vehicle for Pedestrian Headform Protection

2017-03-28
2017-01-1298
Vehicle Hood being the face of a passenger car poses the challenge to meet the regulatory and aesthetic requirements. Urge to make a saleable product makes aesthetics a primary condition. This eventually makes the role of structure optimization much more important. Pedestrian protection- a recent development in the Indian automotive industry, known for dynamics of cost competitive cars, has posed the challenge to make passenger cars meeting the regulation at minimal cost. The paper demonstrates structure optimization of hood and design of peripheral parts for meeting pedestrian protection performance keeping the focus on low cost of ownership. The paper discusses development of an in-house methodology for meeting Headform compliance of a flagship model of Maruti Suzuki India Ltd., providing detailed analysis of the procedure followed from introduction stage of regulatory requirement in the project to final validation of the engineering intent.
Technical Paper

Design Optimization of Trunk Lid Torsion Bar Type Trunk Lid Pop Up Mechanism

2019-10-11
2019-28-0111
Trunk lid (TL) can be opened using hydraulic or pneumatic balancers, coil springs, torsion bars or combination of the above. TL Opening Mechanism specific to Trunk Lid Torsion Bar (TLTB) is being discussed in the paper. After de-latching, TL should open smoothly and stop at such a height that it is visible from driver seat. The system consists of a four bar linkage mechanism, in which the fixed link is formed by BIW Bracket. Connecting link, TL Hinge Arm and Torsion bar arm form the other three links. Hinge has its one end attached to TL and the other end to BIW bracket. Torsion bar arm transfers torque to TL hinge through the connecting link. Major challenges in designing TLTB mechanism are part tolerances, C.G position and Weight variations in individual parts, Torsion bar Raw Material variation, uncertain friction in the system etc.
Technical Paper

Design of Bumper Beam Structure for Pedestrian Protection and Low Speed Bumper Impact(ECE-R42).

2016-04-05
2016-01-1335
The biggest challenge in vehicle BIW design today is to make a light, cost effective and energy absorbing structure. With the increasing competition as well as increasing customer awareness, today’s vehicle has to satisfy several aesthetic and functional requirements besides the mandatory regulatory requirements. Working on global platform is challenging in order to comply with both pedestrian protection and low speed bumper impact (ECE-R42) and, at the same time, to meet the styling intent of reducing the front overhang. Pedestrian lower leg compliance demands space between bumper member and bumper: a condition that reduces the space available for energy absorption during low speed impact (ECE-R42). Therefore, reduction in front overhang poses a problem in meeting both the requirements with limited space. This paper outlines vehicle case study in order to optimize the design of Bumper Beam structure, for complying with regulatory requirements while satisfying the styling intent.
Technical Paper

Intake and Exhaust Ports Design for Tumble and Mass Flow Rate Improvements in Gasoline Engine

2019-04-02
2019-01-0763
In recent years, world-wide automotive manufacturers have been continuously working in the research of suitable technical solutions to meet upcoming stringent carbon dioxide (CO2) emission targets, as defined by international regulatory authorities. Many technologies have been already developed, or are currently under study, to meet legislated targets. In-line with above objective, the enhancement of turbulence intensity inside the combustion chamber has a significant importance which contributes to accelerating the burning rate, to increase the thermal efficiency and to reduce the cyclic variability [9]. Turbulence generation is mainly achieved during the intake stroke which is strictly affected by the intake port geometry, orientation and to certain extends by combustion chamber masking. Conservation of turbulence intensity till 700~720 crank angle (CA) is achieved by optimized shape of combustion chamber geometry and piston bowl shape.
Technical Paper

Design Optimization of Front Hood Structure for Meeting Pedestrian Headform Protection in an Existing Vehicle

2019-04-02
2019-01-0615
Automotive industry today faces the unprecedented challenges both in terms of adapting to changing customer demands in terms of vehicle aesthetics, features or performance as well as meeting the mandatory regulatory requirements, which are being regularly upgraded and becoming stringent day by day. Vehicle hood, being part of vehicle front fascia, needs to fulfill the requirement of vehicle aesthetics as its primary condition. At the same time, every automobile manufacturer has a lineup of older platforms, which are in production and needs to comply with upcoming stricter safety norms, having a structure in under hood area designed as per older philosophy, which further reduces the space available for energy absorption. This makes the structure optimization in vehicle hood area much more challenging. Pedestrian protection - an upcoming regulation in India, has seen some major development in recent times.
Technical Paper

Valve Opening and Closing Event Finalization for Cost Effective Valve Train of Gasoline Engine

2019-04-02
2019-01-1191
With more stringent emission norm coming in future, add more pressure on IC engine to improve fuel efficiency for survival in next few decades. In gasoline SI (spark ignition) engine, valve events have major influence on fuel economy, performance and exhaust emissions. Optimization of valve event demands for extensive simulation and testing to achieve balance between conflicting requirement of low end torque, maximum power output, part load fuel consumption and emission performance. Balance between these requirements will become more critical when designing low cost valve train without VVT (Variable valve timing) to reduce overall cost of engine. Higher CR (Compression ratio) is an important low cost measure to achieve higher thermal efficiency but creates issue of knocking thereby limiting low speed high load performance. The effective CR reduction by means of late intake valve closing (LIVC) is one way to achieve higher expansion ratio while keeping high geometric CR.
Technical Paper

Aerodynamic Design Optimization in Rear End of a Hatchback Passenger Vehicle

2019-03-25
2019-01-1430
Aerodynamic evaluation plays an important role in the new vehicle development process to meet the ever increasing demand of Fuel Economy (FE), superior aero acoustics and thermal performance. Computational Fluid Dynamics (CFD) is extensively used to evaluate the performance of the vehicle at early design stage to overcome cost of proto-parts, late design changes and for time line adherence. CFD is extensively used to optimize the vehicle’s shape, profiles and design features starting from the concept stage to improve the vehicle’s aerodynamic performance. Since the shape of the vehicle determines the flow behavior around it, the performance is different for hatchback, notchback and SUV type of vehicles. In a hatchback vehicle, the roof line is abruptly truncated at the end, which causes flow separation and increase in drag.
Technical Paper

Vehicle Cold Start Mode Fuel Economy Simulation Model Making Methodology

2019-04-02
2019-01-0898
The air pollution and global warming has become a major problem to the society. To counter this worldwide emission norms have become more stringent in recent times and shall continue to get further stringent in the next decade. From OEMs perspective with increased complexity, it has become a necessity to use simulation methods along with model based systems approach to deal with system level complexities and reduce model development time and cost to deal with the various regulatory requirements and customer needs. The simulation models must have good correlation with the actual test results and at the same time should be less complex, fast, and integrable with other vehicle function modelling. As the vehicle fuel economy is declared in cold start condition, the fuel economy simulation model of vehicle in cold start condition is required. The present paper describes a methodology to simulate the cold start fuel economy.
Technical Paper

Optimizing Vehicle NVH Using Multi-Dimensional Source Path Contributor Paradigm.

2018-06-13
2018-01-1542
Automotive Industry is moving towards lightweight vehicle design with more powerful engines. This is increasing a demand for more optimized NVH design. Source-Path-Contributor (SPC) analysis is one of the ways to draw a holistic picture of any NVH problem. In this paper, an NVH problem of low frequency booming noise and steering vibration has been studied in a development vehicle. All three dimensions of SPC paradigm were looked at to propose a feasible and optimized solution at each level of Source, Path and Contributor model. A classical transfer path analysis (TPA) has been done to identify the highest contributing path: transmission mount and suspension arm. Optimization of suspension bush parameter has been carried out using dynamic elastomer testing facility for an improved NVH performance. After identifying source as engine a study of torsional fluctuations due to gas pressure and torsional resonances has been carried out in order to achieve a feasible solution at source.
Technical Paper

Study on Design Optimization of Air Intake Snorkel Using 1D & 3D Tools

2018-04-03
2018-01-0490
With the increase in customer expectations related to engine performance and vehicle NVH, it has become the need of the hour for automotive industry to continuously use state of-the-art designs. These dynamic concepts require innovative simulation techniques correlated with testing to value engineer the optimal design and further validations. Compact engine room packaging and futuristic aesthetics changes in styling have further magnified these challenges. Packaging air intake system and positioning air intake snorkel are among such challenges that play a critical role for improving engine performance and life. The objective of this paper is to propose an approach for optimizing design and position of air intake snorkel to meet desired intake air temperature, noise targets with no water entry in to engine. Full vehicle computational fluid dynamics (CFD) simulation is performed for predicting air intake temperature, water wading and 1D simulation for suction flow noise.
Technical Paper

Fuel Efficient Algorithm for Climate Control in Next Generation Vehicles

2017-01-10
2017-26-0370
Automobile industry is shifting its focus from conventional fuel vehicles to NexGen vehicles. The NexGen vehicles have electrical components to propel the vehicle apart from mechanical system. These vehicles have a goal of achieving better fuel efficiency along with reduced emissions making it customer as well as environment friendly. Idle start-stop is a key feature of NexGen vehicles, where, the Engine ECU switches to engine stop mode while idling to cut the fuel consumption and increase fuel efficiency. Engine restarts when there is an input from driver to run the vehicle. There is always a clash between the Engine ECU and automatic climate control unit (Auto-AC) either to enter idle stop mode for better fuel efficiency or inhibit idle stop mode to keep the compressor running for driver comfort. This clash can be resolved in two ways: 1 Hardware change and, 2 Software change Hardware change leads to increase in cost, validation effort and time.
Technical Paper

Aerodynamic Development of Maruti Suzuki Vitara Brezza using CFD Simulations

2017-01-10
2017-26-0268
Recent automotive trend shows that customer demand is moving towards bigger size vehicle with more comfort, space, safety, feature and technology. Global market of SUV is projected to surpass 21 million units by 2020. Despite economic slowdown and weak new car sales worldwide, India and China will continue to be primary market for SUV due to sheer size of population, urban expanding middle class and larger untapped rural market. However, stricter emission norms push for clean and green technology and unfavorable policy towards use of diesel vehicle has made the SUV design very challenging due to conflicting needs. Due to bigger size of vehicle, aerodynamic design plays an important role in achieving emission targets and higher fuel efficiency. This paper highlights the aerodynamic development of Maruti Suzuki Vitara Brezza, which is an entry level SUV vehicle with high ground clearance of 198 mm and best in class fuel economy of 24.3 kmpl.
Technical Paper

Optimization of Simulation Channels for Inverse FRF Calculation on 6-Axis Road Load Simulator: An Experimental Approach

2017-01-10
2017-26-0303
Nowadays, Road Load Simulators are used by automobile companies to reproduce the accurate and multi axial stresses in test parts to simulate the real loading conditions. The road conditions are simulated in lab by measuring the customer usage data by sensors like Wheel Force transducers, accelerometers, displacement sensors and strain gauges on the vehicle body and suspension parts. The acquired data is simulated in lab condition by generating ‘drive file’ using the response of the above mentioned sensors [2]. For generation of proper drive file, not only good FRF but ensuring stability of inverse FRF is also essential. Stability of the inverse FRF depends upon the simulation channels used. In this paper experimental approach has been applied for the optimization of the simulation channels to be used for simulation of normal Indian passenger car on 4 corners, 6-Axis Road Load Simulator. Time domain tests were performed to identify potential simulation channels.
Technical Paper

Development of Test Method to Validate Synchronizer Ring Design for Torsional Fluctuations in Manual Transmission

2016-02-01
2016-28-0012
Manual transmissions dominate the Indian market for their obvious benefit of low cost and higher mechanical efficiency resulting in higher fuel economy. Synchronizer system in manual transmission enables smoother and quieter gear shifting. Synchronizer ring is the key element which provides the necessary frictional torque to synchronize the speed of gear and sleeve for smooth shifting. During vehicle running, synchronizer rings are free to rattle inside the indexing clearance. High engine torsional excitation and low clutch dampening can result into increased fluctuation of the input shaft of transmission. High fluctuation or lower contact area of synchronizer ring can lead to damage on the index area. This damage may cause hard gear shifting and gear shift blockage in case of extreme damage.
Technical Paper

Simulating Real World Driving: A Case study on New Delhi

2016-02-01
2016-28-0236
In the Indian Context, Fuel Economy of a vehicle is one of key elements while buying a Car. The fuel economy declared by OEMs (Original Equipment Manufacturers) is one of the key indicators while assessing the fuel economy. However it is based on a standard driving cycle and evaluated under standard conditions as mandated by emission legislation. As the driving pattern has a major influence on fuel economy, the objective of this paper is to study real world driving patterns and to define a methodology to simulate a real world driving cycle. A case study was done on Delhi City, by running a fleet of vehicles in different traffic conditions. Thereafter data analysis like acceleration %, specific energy demand per distance, Acceleration vs. Vehicle Speed distribution etc. was done with the help of MATLAB. The final validation of cycle was done by comparing Lab results with on-road Fuel Economy data.
Journal Article

Improving STL Performance of Automotive Carpets with Multi-layering and Effective Decoupling

2015-01-14
2015-26-0136
Automotive floor carpet serves the purpose of insulating airborne noises like road-tire noise, transmission noise, fuel pump noise etc. Most commonly used automotive floor carpet structure is- molded sound barrier (PE, vinyl etc.) decoupled from the floor pan with an absorber such as felt. With increasing customer expectations and fuel efficiency requirements, the NVH requirements are increasing as well. The only possible way of increasing acoustic performance (Specifically, Sound Transmission Loss, STL) in the mentioned carpet structure is to increase the barrier material. This solution, however, comes at a great weight penalty. Theoretically, increasing the number of decoupled barrier layers greatly enhances the STL performance of an acoustic packaging for same weight. In practice, however, this solution presents problems like- ineffectiveness at lower frequencies, sudden dip in performance at modal frequencies.
Technical Paper

Consideration of Indian Turbans in Vehicle Design

2016-02-01
2016-28-0044
India is a country of diversity. From North to South, east to west, one can find altogether different culture, religions, spoken languages, foods, weather conditions, people lifestyles, dressing styles etc. This vast diversity of India poses a great challenge in front of Indian Automobile Manufacturers, so as to assimilate all the requirements (of this big nation) in one single car (design). For example, many people in India wear turban (out of their religious beliefs or cultural heritage). So, is it required to keep enough consideration for Turban wearing population in vehicle design? Turban, unlike caps or hats, is something which is tied on the head (not just only kept). It is something which cannot be removed whenever required. So, it can somehow be considered as an integral part of body (as an added head dimension). So, it becomes all the more important to thoroughly understand this aspect & keep a consideration for the same in vehicle design.
Technical Paper

Methodology for Establishing Damage Criteria Using Probability Distribution Function on Component Level Tests - a Case Study

2016-02-01
2016-28-0041
Automobile components are usually subjected to complex varying loads. Thus, fatigue failure is a common mode of failure in automobile components. Accurately predicting the fatigue life is the key point for light weight and also reliability design of automobile components. Various life prediction theories are being used in the automotive industry for damage analysis using material S-N curves. However, due to variability in manufacturing, material spec etc. it is difficult to predict the experimental lives using conventional theories. Probability based statistical modeling is prevalent in the industry for life prediction. Probabilistic plots of cycles to failure to constant amplitude loads are plotted and used for prediction purpose. As the component is subjected to varying loads in real world, defining a single parameter i.e. damage would be more relevant compared to loads.
Technical Paper

Hybrid Controls Comparison on HILs Using a Modular Soft Platform

2016-02-01
2016-28-0026
Hybrid Electric Vehicle (HEV) Controls Development is an important aspect to realize the goals of Powertrain Electrification i.e. fuel economy and emission improvement. Keeping that in mind, development engineers need to formulate numerous control strategies. Once the control strategy is evaluated and frozen, it typically does not change from one vehicle model application to another. However, it may happen that Electronic Control Unit (ECU) manufacturer may change depending on the sourcing strategy. Therefore, in order to maintain uniformity, it may be required to compare control strategy of a finished ECU product frozen for one model application to be compared with new ECU sourced through another manufacturer. This paper discusses a methodology to compare control strategy of two ECU’s sourced from different ECU manufacturers with identical control requirements.
Technical Paper

Thermal Radiation Heat Transfer Model and Its Application for Automobile Exhaust Components

2016-02-01
2016-28-0051
Shielding vehicle underbody or engine room components from exhaust heat is becoming a difficult task with increasing packaging constraints, which lead to the proximity of components with high temperatures of the exhaust systems. Heat insulators are provided to protect various components from exhaust system parts. Generally the requirement of heat insulators are fixed on the basis of benchmarked temperatures measured on vehicles with similar layout, during the initial phase of vehicle design. Also various CFD techniques are available to predict the surface temperatures on components in order to determine the necessity of a heat insulator. The aforementioned techniques use radiation and convection heat transfer effects on a complete vehicle model and the overall process generally takes considerable time to provide the results. This paper deals with a theoretical approach to predict the temperatures on nearby components due to exhaust system heat.
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