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With advancement of technologies, upgradation of validation procedures and equipment on engine dynamometer test bed is required to simulate environment similar to vehicle and achieve accurate test results. A coolant conditioning system helps in achieving desired temperatures of coolant in the circuit during engine validation. However, unlike radiator type cooling systems of vehicles, conventional coolant conditioning systems on engine test beds generate negative pressure in circuit which poses a risk of coolant boiling, loss of intended heat transfer and hence higher temperature in cylinder head which can be detrimental for durability of critical components like valves, valve seats etc. This paper encompasses a stepwise approach followed to attain near-vehicle coolant pressure conditions for a naturally aspirated engine. Coolant used for this experiment was 50:50 (by volume) ethylene glycol and water mixture.

In the modern automobile scenario in developing countries, customers are getting more meticulous and market more competitive. Now even the budget vehicle customer expects desirable vehicle performance in specific use cases of the vehicle that were previously not focused by designers. Hence, the focus on perceived quality challenges automobile engineers to go the extra mile when it comes to the cost-effective design of parts that are tangible to the customer. A vehicle's cowl cover is one such exterior component. The primary functions of this part are to provide air intake opening for the HVAC system and cover the components like wiper motor. The aesthetic function is to cover the gaps between windshield, hood, and fender as seamlessly as possible. A specific role of cowl cover, which calls for a designer's attention, is its load-bearing capability.

Three-cylinder Engine without balancer shaft is a recent trend towards development of lightweight and fuel-efficient powertrain for passenger car. In addition, customer's expectation of superior NVH inside vehicle cabin is increasing day by day. Engine mounts address majority of the NVH issues related to transfer of vibration from engine to passenger cabin. Idle vibration isolation for a three-cylinder engine is a challenging task due to possibility of overlapping of Powertrain's rigid body modes with engine's firing frequency. This Overlapping of rigid body can be avoided either by modifying mount characteristic or by changing the position of mounts based on multi-body-dynamics (MBD) simulation. This paper explains about two types of engine mounting system for a front-wheel drive transversely mounted three-cylinder engine. The base vehicle was having three-point mounting system i.e. all three engine mounts were pre-loaded.

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.

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.

In automotive Front End Accessory Drives (FEAD), the crankshaft supplies power to accessories like alternators, pumps, etc. FEAD undergoes forced vibration due to crankshaft excitation, dynamic tension fluctuations can cause the belt to slip on the accessory pulleys. By considering the criticality of the system, when engine mounting is longitudinally to the vehicle which makes it directly exposed to the air flow containing foreign particles which may cause the damage to the FEAD system and deteriorate the intended functionality. FEAD cover is introduced in the system to enhance belt-pully system functionality by restricting the entry of foreign particles during engine operation. This paper contains a study of FEAD cover failure and provides the stepwise approach to capture such issue during novel model development for 4 cylinder naturally aspirated engine during engine bench testing.

With strict upcoming regulation norms, it becomes a challenging task for automotive industry to develop highly efficient engine that meets all the regulation requirements. The focus of automakers is to utilize fuel energy in most efficient way and to reduce the energy loss from the engine to improve thermal efficiency. Heat loss to the cooling medium is one of the prime losses inside the combustion chamber. Thermal barrier coating is used to reduce heat losses across combustion chamber surfaces (Piston, head, valves and cylinder liner) as it provides good insulation because of the prominent properties of coating materials like low thermal conductivity, low heat capacity, high melting point etc. This paper presents application and impact of thermal swing coating on thermal efficiency. Thermal swing coating material follows gas temperature quickly throughout the cycle which reduces the temperature difference between gas and coating surface and thus reduces the heat loss.

Radiators are one of the major components in the automotive engine cooling system. The road excitations from the frame to the radiator are dampened using rubber bushes. In this work, we analyzed a radiator sub-assembly with bushes by applying acceleration which are recorded at the center of gravity of the radiator. The radiator is considered as the concentrated mass which is attached to the upper and the lower radiator tank which is further connected to the frame through the bushings. An implicit transient dynamic analysis is set up. The hyper elastic coefficients for EPDM rubber are determined using the experimental data fit and structural damping coefficients are applied. When excited by the acceleration applied at center of the radiator component, the rubber bushes are deformed severely. Moreover, the analysis shows high strains in certain location on the upper bush where the part showed actual failure in the testing.

With the increasing competition in the automotive industry, customer experience & satisfaction is at the top of every organization's goals. The customers have evolved & NVH refinement has become the parameter for their decision making in buying a car. The major source of rumble noise in a vehicle is the induced vibrations due to combustion forces in an IC engine. These vibrations are then transferred to the vehicle body through engine mounts. Hence engine mounts play a key role in defining the NVH & the ride performance of any vehicle. However, it is infeasible to validate every mount design through the physical test as it will be both costly & time-consuming. But multiple design iterations can be verified by the CAE approach quite effectively. This paper focuses on the novel CAE approach to evaluate the mount vibrations due to engine dynamics. The process involves preparing a FEA model of the complete Powertrain system.

Rapidly changing emission and fuel efficiency regulations are pushing the design optimization boundaries further in the Indian car market which is already a very cost conscious. Fuel economy can be improved by reducing moving parts friction and weight optimization. Driveline or Transmission power losses are major factor in overall efficiency of rotating parts in a vehicle. Transmission efficiency can be improved by using low viscosity oil, reducing oil quantity and reducing churning losses in car transmission. Changes like low viscosity and reduced oil volume give rise to challenges like compromised lubrication and durability of rotating parts. This further leads to extended design cycles for launching new cars with better transmission efficiency and fuel economy into the market. Design cycle time can be reduced by using CFD simulation for oil flow validation in the early design stage.

NVH refinement of passenger vehicle is essential to customer acceptance for premium or even mid-size segment passenger cars. Hydraulic engine mount is becoming common for these segments to reduce engine bounce, idle shake and noise transfer to passenger cabin. Modern layout of hydraulic mount with integrated engine-bracket and smaller size insulator has made it cost-effective to use due to reduction of cost gap from conventional elastomeric mounts. However the downsizing and complex internal structure may create some new types of noises in passenger cabin which are very difficult to identify in initial development stage. Main purpose of hydraulic mount is to provide high damping at low-frequency range (6~15 Hz) and to isolate noise transfer from combustion engine to passenger cabin within wide frequency range (15~600 Hz).This paper emphasizes on challenges and problems related to hydraulic mount development.

Quieter cabins are indispensable in today’s evolving automobile industry. The effective isolation of vehicle noise and vibrations are essential to achieve the above. Since, low frequency powertrain induced NVH has been one of the major contributors affecting noise and vibration levels inside the passenger cabin. Thus, use of hydraulic mounts is a natural choice for all major OEMs. The objective of this study is to optimize the design of the hydraulic mount de-coupler unit, to reduce the abnormal noise felt inside the cabin. This condition was observed when the vehicle was driven at 20~30 km/h over undulated road surface, found very often in Indian drive conditions. Due to lack of accuracy and repeatability errors during NVH data acquisition in actual driving condition, the above road profile was captured and subsequently simulated in an acoustically treated BSR (Buzz, Squeak and Rattle) four poster simulator.

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.

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.

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.

As the automotive market is very dynamic and vehicle manufactures try to reduce the vehicle development cycle time, more focus is being given to CAE simulation technologies to reduce the design cycle time and number of physical tests. CAE engineers are continuously working on improving the accuracy of CAE simulation, such as using flexible body dynamic simulation in place of linear static analysis. Strength calculation under dynamic condition is more accurate as compared to static condition as it gives more clear understanding of stress variation with motion, contacts and mass inertia. Failure has been observed in new development of valve train pivot screw under test conditions. As per linear static analysis, design was judged OK. Normal linear static analysis is a two stage process. In first stage loads are calculated by hand or peak loads are taken from multibody dynamics (MBD) rigid body analysis.

Over the years, Fuel efficiency and cabin comfort of vehicle has become increasingly important in buying decision and can significantly give competitive edge to the vehicle in marketplace. Weight and friction reduction of rotating and reciprocating components in engines is one of the proven approaches to improve the efficiency of internal combustion engine. To reduce the friction, the general approach is to use low viscosity engine oils, improve the surface finish and reduce the contact area of sliding elements, switch over from sliding contact to rolling contact etc. However sometimes this approach has adverse impact on engine NVH characteristics due to occurrence of abnormal transient noise due to mechanical knocking of the components in specific operating conditions.

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.

In order to meet the challenges of future CAFE regulations & pollutant emission, vehicle fuel efficiency must be improved upon without compromising vehicle performance. Optimization of engine breathing & its impact on vehicle level fuel economy, performance needs balance between conflicting requirements of vehicle Fuel Economy, performance & drivability. In this study a Port Fuel Injection, naturally aspirated small passenger car gasoline engine was selected which was being used in a typical small passenger car. Simulation approach was used to investigate vehicle fuel economy and performance, where-in 1D CFD Engine model was used to investigate and optimize Valve train events (Intake and exhaust valve open and close timings) for best fuel economy. Engine Simulation software is physics based and uses a phenomenological approach 0-D turbulent combustion model to calculate engine performance parameters. Engine simulation model was calibrated within 95% accuracy of test data.

Vehicle cabin comfort emphasizes a specific image of a brand and its product quality. Low frequency powertrain induced noise and vibration levels are a major contributor affecting comfort inside passenger cabin. Thus, using hydraulic mount is a natural choice. Introduction of lighter body panels coupled with cost effective hydraulic mounts has resulted in some additional noises on rough road surfaces which are challenging to identify during design phase. This paper presents a novel approach to identify two such noises i.e. Cavitation noise and Mount membrane hitting noise based on component level testing which are validated at vehicle experimentally. These noises are encountered at 20~30kmph on undulated road surfaces. Sound quality aspect of such noises is also studied to evaluate the solution effectiveness.