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With the advancement of regulatory norms in automobile industry, there is a challenge to meet performance efficiency targets, especially with a lightweight platform, while providing superior driving experience to customers. The shift towards weight optimization, makes the vehicle structure more susceptible to transfer a diverse range of noise and vibrations through body. Although most undesirable noises perceived inside the cabin can be reduced by superior technology engine mounts and NVH packaging, all such solutions lead to cost addition. Intelligent considerations in part design can be used to supplement predictable transfer paths to quell the unwanted vibrations. One such case is of the gear whine noise in certain rpm bands caused by inherent gear meshing frequency coinciding with natural frequency of an engine mounting bracket.

The Indian passenger vehicle market has grown by more than 40% by volume in the last decade and has reached a record high in FY23. This has created a more diverse and demanding customer base that values interior design and quality. The modern customer expects a high level of aesthetics and sophistication in their vehicle interiors - including in the luggage area. The Luggage Cover (Parcel Tray) is a component in the luggage area of a passenger vehicle that is used to conceal the luggage & improve its aesthetics. The cover is generally made of thermoplastic material with rotating hinges and is held in its place by the compression from the back door, which is frequently opened and closed. The parts that connect the cover to the door (usually an elastomer interface on the thermoplastic tray) tend to change over a period due to climatic conditions and leads to rattling concerns over a period.

With the advent of upcoming stringent automobile emission norms globally, it is inevitable for original equipment manufacturers (OEMs) to shift towards greener alternatives. Use of compressed natural gas (CNG) is a preferred solution as it is a relatively clean burning fuel and it doesn’t have significant loss in vehicle efficiency and performance. Modern day customers are more aware and sensitive towards vehicle noise, vibration and harshness (NVH). Hence, OEMs must cater to this demand through optimized design and layout. In a passenger vehicle, CNG is stored at high pressure and delivered to injectors after pressure reduction at a regulator. During engine idling, the opening and closing motion of the CNG injector generates back pulsation and these pulsations cause vibrations which may propagate through other components in the delivery path and perceived as noise inside vehicle cabin.

Exhaust system of an automobile is primarily employed in automobile to purify exhaust gases and reduce noise due to combustion. However, a side-effect of the above function is the increase in backpressure. As specified in various literatures, an increase in backpressure can lead to a deterioration on engine performance (Power & torque). Benefit of backpressure reduction can be further taken in terms improving the power & torque of engine or improving the fuel economy. With growing concerns related to global warming and CO2 emissions, reducing exhaust back pressure is one of the promising areas in engine design in order to improve the fuel economy of the automobile and achieving carbon neutrality targets. However, reducing the back pressure generally tends to deteriorate the noise attenuation performance of the Exhaust system.

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

During the conceptualization of vehicle, it is big challenge for automotive manufacturer to design a vehicle which has an excellent aesthetic looks as well as meet the stringent vehicle regulations. In the vehicle styling, bumper plays an important role in deciding of the contemporary looks of the vehicle. To improve customer satisfaction, it is important to design a bumper which provides feeling and sense of durability. In addition, bumper should sustain low-speed impact and protects the peripheral components such as parking lights, headlamps, hood, back door and safety related installed equipments like Rear parking camera, parking sensors, etc. Bumper should be dent resistant and be able to regain its original shape on removal of the applied load. An elegant design of bumper should be light weight with high strength. This paper explains about a new CAE methodology developed to simulate the real life loading condition of bumper and to calculate the deformation in the bumper.

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.

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.

Single body architecture designed for various global markets and subjected to varied load cases is a challenge for Body in White (BIW) engineers. Optimization of structural design to meet regulatory, insurance and assessment requirements is an iterative and time consuming task. With focus on reduction of vehicle's damageability and ease of repairability Original Equipment Manufactures (OEM), insurance companies and Research Council for Automobile Repairs (RCAR) [1] are striving for better designs. A space constraint crash box structure installed behind the bumper plays a significant role in absorption of energy, before transmitting to longitudinal rails. In this study, crashworthiness of a multipurpose crash box for a hatch segment vehicle is presented with the various design of experiments conducted with a focus on light weighting, cost and ease of manufacturing.

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.

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.

Hydromount plays an important role in isolating vibration during idling. To meet ideal NVH criteria, a properly tuned Hydromount is required otherwise there will be abnormal noise due to cavitation effect. Cavitation noise is such a noise which is very difficult to identify in initial vehicle development stage. The effects of cavitation in the Hydromount become increasingly important for noise and performance goals. Cavitation is the formation and collapse of vapor bubbles in a working fluid when local static pressure falls below the vapor pressure of the working fluid. Technique to detect cavitation in Hydromount is presented in this paper. The countermeasure technique concentrates on increasing the fluid flow rate betweens fluid chambers. The results for different design countermeasure performance have been measured and the performance is compared in the vehicle. The results of vehicle level tests show the same trends as bench test results.

In developing countries steel wheel is generally used in the low end passenger cars. Steel wheel has a hole at center, known as wheel bore which give the provision for tightening & un-tightening of axle nut. Due to this hole, the surrounding parts are visible which reduces the aesthetic appearance of the wheel. To cover the center portion of the wheel, “Cap, Wheel Center” also called as “Center Cap” is used, which is an aesthetic oriented part as shown in Figure 1. Center Cap is designed in such a manner that it can be easily removed & re-fitted during the service of vehicle. This paper explains the systematic methodology to optimize the weight of the “Center Cap” without compromising the performance & aesthetic appearance. Various analytical calculations have been done to achieve base line value of the design which was further justified using CAE (computer aided engineering) to optimize the performance & weight.

Engine noise is a major source of noise inside the vehicle compartment. Recently, the quietness of the occupant cabin has become an important dimension to the quality of product. OEMs are finding it challenging to meet the customer expectations for “Powerful yet quiet” attribute. Several focused studies have been made to reduce the under hood component noise in automobiles. This paper summarizes the optimization of the vibro-acoustic sensitivity (VAS) of the engine mounts of a small car engine. The contribution of each engine mount on the structure-borne noise transfer inside the cabin is the prime focus of this study. In the current analysis, the body side and engine side mounting bracket stiffness analyses are carried out to reduce the vibro-acoustic transfer. Experimental methods like conventional FRF, on-road data acquisition and physical prototyping have been used.

As automobile design has become more sophisticated, the level of noise inside the vehicle has been dramatically reduced. The sources of noise which were previously ignored have now become relatively more significant, and it has become desirable to reduce the noise from such sources. The noise from the fuel system may be low but the fact that it operates continuously whether or not vehicle is moving, makes its noise level more noticeable. So in order to achieve overall better NVH characteristics in a car it is important to minimize the noises from fuel delivery system. The current paper addresses the fuel pulsation noise from fuel delivery line and describes countermeasure approach for noise reduction using an Experiment Based Design approach (EBD).

In a highly competitive market, one of the major challenges for an automobile designer is to lower the product cost while improving the performance. Therefore, from the vehicle comfort point of view, achieving a good ride, handling and NVH performance, while satisfying the low cost and low weight target needs attention from the concept stage of the development cycle. To achieve this balance, it is important to optimize the static and dynamic stiffness of the vehicle body. This paper focuses on the effect of vehicle body stiffness on the ride, handling and NVH parameters. It also addresses the relation between static and dynamic stiffness of the vehicle. The correlation of the stiffness values with the ride, handling and NVH performance is also studied through various experiments on the actual vehicle