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Technical Paper

Innovative Simulation Approach to Analyze and Add Value to Upcoming Complex Drive Cycle (WLTC) for Passenger Cars

2013-11-27
2013-01-2801
Vehicles which are sold and put into service in a country have to meet the regulations and standards of that country. Every country has a separate regulation and approval procedure which requires expensive design modifications, additional tests and duplicating approvals. Thus, there is the need to harmonize the different national technical requirements for vehicles and form a unique international regulation. With this rationale, the World Forum for Harmonization of Vehicle Regulations of the United Nations Economic Commission for Europe (UN/ECE/WP29) has brought governments and automobile manufacturers together to work on a new harmonized test cycle and procedure which is to be adopted around the world. This lead to the development of Worldwide Harmonized Light Duty Test Procedures (WLTP) and Cycles (WLTC). The test procedure is divided into 3 cycles, depending on a power to mass ratio of the tested vehicle.
Technical Paper

Analysis of Thermal Balance of Diesel Engine and Identification of Scope for Waste Heat Recovery

2013-11-27
2013-01-2744
Diesel engines as prime movers for passenger cars are becoming popular, primarily due to their superior thermal efficiency. However, the peak thermal efficiency does not exceed 35 to 40% even in the best engines. Huge efforts are being put in to improve engine efficiencies to meet ever stringent fuel economy requirements. Such efforts are mainly focused on combustion improvement and parasitic losses reduction. However, a large part of the energy input to engine is lost to cooling system, exhaust gases and other heat losses. Such losses are higher at part and low loads which is where the engine operates in normal usage conditions. This paper analyses in detail the various energy losses at different engine operating regimes. Quantification of losses and understanding of loss mechanism serves as a starting point for future technologies to recover the lost energy. Quantification of losses: Losses in different systems are quantified at different engine operating regimes.
Technical Paper

Base Engine Value Engineering for Higher Fuel Efficiency and Enhanced Performance

2013-11-27
2013-01-2748
To sustain market leadership position one has to continuously improve their product and services so that on one hand customer expectations are met and on the other hand business profitability is maintained. Value engineering is one of the approach through which we can achieve these two objectives simultaneously. Enhancing the value of running products is always a challenge as there is limited scope and flexibility to modify the current design and processes. Value engineering approach, integrated in product development cycle, brings great opportunity to upgrade the new and running products. This study reveals approach to upgrade the base engine of Maruti Alto. Upgraded engine is used in Alto 800 vehicle launched in October 2012. Improvement points were studied based on the business requirement, market competition, and legislative requirements. Based on functional improvement points, all the design parameters were studied and finalized.
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.
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

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

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

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

Evaluation of Sound Radiation from Exhaust Muffler Shell-A Novel Experimental Approach

2013-03-25
2013-01-0116
Shorter product development cycles, densely packed engine compartments and intensified noise legislation has increased the need for accurate predictions of passenger cars Exhaust system noise at early design stages. The urgent focus on the increasing CO2 emissions and the efficiency of IC-engines as well as upcoming technologies might adversely affect the noise emission from an exhaust system, so it is becoming increasingly important to evaluate the sub system level noise emissions in an early design stage in order to predict and optimize the exhaust system performance. Engine performance and vehicle NVH characteristics are two important parameters on which the design of the exhaust system has major influence. The reduction of exhaust noise is a very important factor in controlling the exterior and interior noise levels of vehicles, particularly to reach future target values of the pass-by noise and sound engineering for the vehicle.
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 Bumper Beam Structure for Pedestrian Protection and Low Speed Bumper Impact

2016-02-01
2016-28-0210
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. While working on global platform, it is challenging to comply with both pedestrian protection and low speed bumper impact (ECE-R42) and at the same time meeting 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

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.
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

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

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

Latch Failure Prediction for Side Door Intrusion Test in CAE and Its Correlation with Physical Testing

2015-01-14
2015-26-0159
During vehicle development, numerous test are done to ensure safety & durability of the vehicle. One such test prescribed by regulation (IS 12009:1995) is side door intrusion test (SDIT). This test evaluates strength requirement of a side door of passenger cars to minimize the safety hazards caused by intrusion into passenger compartment in a side impact accident viz., initial, intermediate and peak crush resistance. In current scenario the passenger car manufacturers are striving hard on cost reduction by reducing the development cost. Thus, to predict the exact vehicle performance before its prototype stage is vital. This can be achieved by evaluating performance by the help of Computer aided engineering (CAE) During the SDIT, the load is applied to the outer surface of the door in an inward direction. This inward force applied by loading device is resisted by the door assembly, while door is pivoted at door latch and hinge.
Technical Paper

Study of Effect of Variation in Micro-Geometry of Gear Pair on Noise Level at Transmission

2015-01-14
2015-26-0130
Gear noise and vibration in automobile transmissions is a phenomenon of great concern. Noise generated at the gearbox, due to gear meshing, also known as gear whine, gets transferred from the engine cabin to the passenger cabin via various transfer paths and is perceived as air borne noise to the passengers in the vehicle. This noise due to its tonal nature can be very uncomfortable to the passengers. Optimizing micro-geometry of a gear pair can help in improving the stress distribution on tooth flank and reducing the sound level of the tonal noise generated during the running of the gearbox when that gear pair is engaged. This technical paper contains the study of variation in noise level in passenger cabin and contact on tooth flank with change in micro-geometry parameters (involute slope and lead slope) of a particular gear pair. Further scope of study has been discussed at the end of the paper.
Technical Paper

Challenges in Developing Low Rolling Resistance Tyre

2015-03-10
2015-01-0053
Vehicles in India will soon come with star ratings, signifying how environment-friendly they are. The OEM's have braced to improve fuel economy of their existing & upcoming models. Tyre rolling resistance is one of the significant factors for vehicle fuel consumption. Improvement in Fuel consumption is always a prime focus area & to improve it all major factors are considered. In newly launched models, the low rolling resistance tyre development was initiated. The project is challenging as it requires not only achieving low rolling resistance in smaller size tyres (12″ to 13″) but also required to meet other critical vehicle performance parameters like ride, handling, NVH & durability. Effects of Tyre construction, rubber compound were analyzed to achieve lower rolling resistance and better durability of tyre. In addition, the factors affecting the rolling resistance of tyre like inflation pressure, load, and speed in smaller tyre sizes (12″ to 13″) are discussed in this paper.
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.
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