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Technical Paper

Aerodynamic Design Optimization in Rear End of a Hatchback Passenger Vehicle

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

Aerodynamic Development of Maruti Suzuki Vitara Brezza using CFD Simulations

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

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

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

Approach for CO2 Reduction in India’s Automotive Sector

India has gone through a lot of transformation over the last decade. Today it is the 6th largest and one of the fastest growing economies in the world. Rising income level, increased consumerism, rapid growth in urbanization and digitization have attributed to this change. Government focus on “Make in India” for promoting trade and investment in India have ensured that India emerge as one of the largest growing economies in the world. The automotive industry played a pivotal role in the manufacturing sector to boost economic activities in India. The passenger car market has increased 3 times over the last decade and it has led to increased mobility options for many people across India. However, this has put concerns on the country’s energy security and emission levels. According to IEA’s recent report on global CO2 emission, 32.31 Gt of CO2 emissions were from fuel combustion in 2016, out of which transport sector contributed ~25%.
Technical Paper

Base Engine Value Engineering for Higher Fuel Efficiency and Enhanced Performance

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

Challenges in Developing Low Rolling Resistance Tyre

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.
Technical Paper

Consideration of Indian Turbans in Vehicle Design

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

Design Considerations for Plastic Fuel Rail and Its Benefits

Global automobile market is very sensitive to vehicle fuel economy. Gross vehicle weight has substantial effects on FE. Hence, for designers it becomes utmost important to work on the weight reduction ideas up to single component level. Fuel delivery pipe (Fuel Rail) is one such component where there is a big potential. Fuel rail is an integral part of the vehicle fuel system and is mounted on the engine. Primarily it serves as a channel of fuel supply from fuel tank through fuel lines to the multiple fuel injectors, which further sprays the fuel into intake ports at high pressure. Due to opening and closing of injectors, pulsations are generated in fuel lines, so fuel rail also acts as a surge tank as well as a pulsation damper. All these factors make the design of a fuel rail very critical and unique for a particular engine. Materials like aluminum, plastic and sheet metal are generally used for fuel rail manufacturing.
Technical Paper

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

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

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

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).

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

Design of Front Structure of Vehicle for Pedestrian Headform Protection

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

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

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

Effect of Muffler Characteristics on Performance of a Naturally Aspirated SI Engine

With steep increase in fuel prices, there is a strong need for development of better engines with improved performance and emissions. This needs a dedicated effort on engine hardware optimization for lower CO2 levels. Exhaust muffler design is trade-off between noise, backpressure and size/weight. With increase in exhaust muffler volume and simplification of structure there is a corresponding drop observed in exhaust pressures. Study of such a phenomenon would give an insight to benefits achieved based on changes in muffler volumes/structure. This in a way leads to engine improvement. In this paper it has been shown how exhaust muffler characteristics (size and internal construction) impacts engine performance.
Technical Paper

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

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

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

Hybrid Controls Comparison on HILs Using a Modular Soft Platform

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.
Journal Article

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

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

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

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

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

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.