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In today’s competitive scenario, the automotive product life cycle has drastically reduced and all Auto OEM’s are coming up with their updated products with lesser development time. These frequent product upgrades are possible due to use of various digital tools during product design and development. Design and optimization of engine coolpack (powertrain cooling unit) to attain engine cooling performance is one of the important parameter during vehicle development or upgrade. Hence, to keep control over development cost and time of delivery, quick and accurate digital validation capability like one dimensional (1D) simulation is the need of the hour. To predict the powertrain cooling (PTC) performance at vehicle concept stage, when physical prototypes are not available, airflow data from similar developed platforms is considered as an input for 1D simulation.

The growing demand of fuel and cost saving on vehicle, today’s vehicle manufacturer are working on various weight reduction initiative in EV. Lighter weight vehicle have bigger challenges to meet NVH requirement. There are two types of EV called modified and adopted EV’s are commonly in use. The sub frame type of EV system comes under the category of modified EV. In this paper, a mounting system is studied and compared for a cradle type EV as well as sub frame or saddle type EV. MATLAB based optimization tools are used for parameter optimization. The focus is put on the optimization of mounting system location and stiffness for energy optimization, CoG and TRA-EA optimization. The best engine mounting system is compared and adopted based on simulation. 12 DOF studied to address high frequency resonance issues for a sub frame type EV. Finally robustness of the system is checked based on various simulation and optimization.

Transmission of vibration and noise to the occupants and especially driver contributes significantly to the quality perception of the motor vehicle and eventually, it affects the overall ride comfort. These forces mainly reach to customer through tactile locations, i.e. floor, gearshift lever, steering wheel and seat. Showroom/Parking customer drive pattern of a vehicle evinces the steering system and driver’s seat rail vibration as strikingly linked aspect to evaluate human comfort [1]. This paper deals with the study of vibration at steering wheel and seat affecting human comfort at engine idle rpm with AC ON and OFF condition for passenger vehicles. The transmissibility of engine and radiator induced vibrations has been investigated with respect to modal alignment of steering and seat system.

The torque required to tighten any threaded joint is different from the necessary torque to untighten threaded bolt or nut, and it is not observed or widely known since this is a regular and straightforward operation. Typically the torque needed to untighten a newly tightened clamp is around 10% to 30% less than the torque to stretch it further. During tightening a threaded bolt, a significant amount of torque required to overcome friction in the threads and under the nut face. The proportion of the torque used to overcome frictional resistance depends upon the friction value. When we tighten a joint with a coefficient of friction of 0.12, only about approximately 14% of the torque required to stretch the fastener producing the clamp load with 86% of the torque is lost overcoming friction. The torque needed to pull the bolt always acts in the untightening direction, resulted in untightening torque lags behind the tightening torque.

In the modern era of automotive industry, occupant comfort inside the cabin is a basic need and no more a luxury feature. With increase in number of vehicles, the expectations from customers are also changing. One of the major expectations from real world customers is quick cabin cooling thru all seasons, particularly when the vehicle is hot soaked and being used in summer conditions. Occupant thermal comfort inside the vehicle cabin is provisioned by a mobile air conditioning (MAC) system, which operates on a vapor compression-based cycle using a refrigerant. The main components of a direct expansion (DX) based MAC system are, a compressor, condenser, evaporator, and expansion valve. Conditioned air is circulated inside the cabin using a blower, duct system and air vents. The AC condenser is the most critical component in AC circuit as it rejects heat, thereby providing for a cooling effect inside the cabin.

Nowadays, E- commerce and logistics business model is booming in India with road transport as a major mode of delivery system using containers. As competition in such business are on rise, different ways of improving profit margins are being continuously evolved. One such scenario is to look at reducing transportation cost while reducing fuel consumption. Traditionally, aero dynamics of commercial vehicles have never been in focus during their product development although literature shows major part of total fuel energy is consumed in overcoming aerodynamic drag at and above 60 kmph in case of large commercial vehicle. Hence improving vehicle exterior aerodynamic performance gives opportunity to reduce fuel consumption and thereby business profitability. Also byproduct of this improvement is reduced emissions and meeting regulatory requirements.

Today urban buses are equipped with more air consuming devices for an example pneumatic doors, exhaust brake, air suspension and in SCR system to name a few. This has resulted in higher air demand leading to high compressor duty cycles which cause conditions (such as higher compressor head temperatures) that may adversely affect air brake charging system performance. These conditions may require additional maintenance due to a higher amount of oil vapor droplets being passed along into the air brake system. Factors that add to the duty cycle are air suspension, additional air accessories, use of an undersized compressor, frequent stops, excessive air leakage from fittings, connections, lines, chambers or valves, etc. This paper discussed about methodology used to reduce air consumption of air consuming devices used in urban bus application. Performance assessment of air consuming devices with minimum available air pressure was conducted and found satisfactory.

Driving dynamics performance is one of the key customer attributes to be developed during product development. In the vehicle development process, freezing the hardware of the chassis aggregates is one of the major priorities to kick off the other vehicle development activities. The current work involves the development of a multilink suspension for an SUV class vehicle. Typically, each OEM performs several product development loops for maturing the vehicle design. The driving dynamics performance evaluation and tuning happens on a physical vehicle with the driver in Loop. Tuning of suspension parameter on the physical vehicle entails actual replacement of parts/components. This encompasses multiple tuning cycles in product development associated with increased cost and test time. To reduce the product development time and cost while delivering first time right chassis configuration, we took an approach of getting driver-in-loop through driving simulator in the concept phase.

In previous work, AC Compressor Cycling (ACC) was modeled by incorporating evaporator thermal inertia in Mobile Air Conditioning (MAC) performance simulation. Prediction accuracy of >95% in average cabin air temperature has been achieved at moderate ambient condition, however the number of ACC events in 1D CAE simulation were higher as compared to physical test [1]. This paper documents the systematic approach followed to address the challenges in simulation model in order to bridge the gap between physical and digital. In physical phenomenon, during cabin cooldown, after meeting the set/ target cooling of a cabin, the ACC takes place. During ACC, gradual heat transfer takes place between cold evaporator surface and air flowing over it because of evaporator thermal inertia.

BSR noise is an important parameters for customer discomfort. According to a market survey, squeaks and rattles are the third most important customer concern in cars after six months of ownership. The high quality acoustic environment of a car, annoying noises like buzz, squeak, and rattle is related to various parameters such as material assembly, tolerance, aging, humidity, surface contact, and surface hardness. BSR is originated from frictional movement between two parts or from the impact between two parts. The rattle noise is caused when surfaces close to each other move perpendicular to each other due to insufficient attachments or insufficient structural strength. In our study, we have shown the impact of various front suspension component in front suspension assembly on BSR noise and also the method to detect and attenuate the same. A methodical analysis process is shown to identify the contributing part and resolve the BSR issue.

The automotive industry is facing a challenge as efficiency improvements are required to address the strict emission norms which in turn requires high performance downsized, lightweight IC engines. The increasing demand for lightweight engine needs high strength to weight ratio materials. To meet high strength to weight ratio, castings are preferable. However due to strength limitations for critical crankshaft applications, it forces to use costly forgings such as micro alloyed forging steel and Martensitic (after heat treatment) forging steel. To reduce the cost impact, high strength Austempered Ductile iron (ADI) casting is developed for crankshaft applications to substitute steel forgings. Austempered Ductile Iron is having an excellent mechanical properties due to aus-ferritic structure. The improved properties of developed ADI Crankshaft over steel forged crankshaft offers additional weight advantage.

HVAC system design has an accountability towards acoustic comfort of passengers of a vehicle. Owing to larger cabin volume of a bus, multiple air blowers have to be installed to ensure comfort of passengers. Such multiple blowers produce significant flow induced noise inside the cabin. For commercial success, it becomes essential to predict intensity of such a flow induced noise at very early stages in product development. Conventionally sliding mesh based CFD approach is deployed to predict flow and turbulence noise around each blower. However due to complexity, this method becomes computationally intensive resulting in cost and time inefficiency. Hence it is desirable to innovate around an alternative rapid, reliable prediction method, which ensures quick turnaround of prediction.

In electric vehicles, the powertrain mounting system design has challenges different from conventional internal combustion engine (ICE) powertrains. Due to the absence of source noise, the customer predominantly experiences the buzz, squeak and rattle (BSR) noise. The 6 degrees of freedom (DOF) modal frequency target is less stringent than a three-cylinder or four-cylinder ICE powertrain. The durability loads in EV also differ due to less powertrain weight. In this paper, a study has been carried out about balancing all three main performance parameters of modal decoupling, BSR and durability through powertrain mount design optimization. The article shows that a carryover ICE powertrain mount has typical issues in Electric Vehicle (EV). A case study has discussed in detail how to manage those issues. Finally, it is concluded that a particular focus is required during an early stage of mount design to address these challenges for an EV.

Leaf springs are used for vehicle suspension to support the load. These springs are made of flat sections of spring steel in single or in stack of multiple layers, held together in bracketed assembly. The key characteristics of leaf spring are defined as ability to distribute stresses along its length and transmit a load over the width of the chassis structures. The most common leaf spring steels are carbon steels alloyed with Cr and micro-alloyed with Ti, V and Nb. The specific thermomechanical process and alloying elements result in specific strength and fatigue properties for spring steels. The unique properties which facilitate use of spring steel in leaf spring suspensions are ability to withstand considerable twisting or bending forces without any distortion. The microstructure of these steel determines the performance and reflects the process of steel manufacturing. The performance is mainly determined by evaluating fatigue life durability.

Gear rattle is due to impact noise of unloaded gears in transmission having freedom to move in backlash region. Engine order vibrations in the presence of backlash in meshing pairs induce the problem. It is a system behavior wherein flywheel torsional vibrations, the pre-damper characteristics and transmission drag torque plays a vital role in an engine idle condition (hot & cold). Idle rattle is a severe issue, which is highly noticeable in cold condition or after 1st engine crank. Gear rattling observed in idle condition is idle gear rattle or neutral gear rattle, specifically in cold condition is a “Cold idle rattle” and this is one of the critical noise parameters considered for entire vehicle NVH. Damper mechanism in the clutch, is used to serve better isolation (by reducing the input excitation to transmission parts) of vibrations between engine and transmission their by reducing gear rattle intensity.

Corrosion in automotive industry is broadly categorized into cosmetic & perforation corrosion. Cosmetic corrosion comprises of superficial red rust which is deleterious to the overall aesthetic appeal of the vehicle but can be rectified. Perforation corrosion involves complete erosion of the panel, compromising structural integrity of the respective part. Perforation corrosion demands part replacement. In order to tackle this menace, automotive OEMs have formulated varied corrosion strategies in terms of selection of appropriate substrate, part design & surface protection scheme. Validation of various corrosion strategies become pivotal during the development phase of various parts and assemblies. Traditionally, Salt Spray Test (SST) has been used to determine corrosion life of materials/parts/assemblies. This test however does not simulate real-world conditions.

The properties of Cold drawn electric resistance welded, as drawn (CEW-AD) tubes and Electric resistance welded (ERW) tubes are vastly different. Deformation resistance of ERW tube is less than half that of CEW-AD tube, hence not preferred for structural applications, common practice being the use of CEW-AD tubes for Chassis cross members in vehicles. A new cost effective high strength ERW tube was developed which has been proved to be superior to the currently used CEW-AD tubes in terms of mechanical properties, formability, consistency and uniformity of the properties over the tube length. The newly developed tube through use of special micro alloy grade in ERW has made it possible to eliminate some of the manufacturing processes like annealing, phosphating, cold drawing etc. which has led to considerable cost saving.

In automobile design, a rear-engine layout mainly espoused for small entry-level cars and light commercial vehicles for three reasons - packaging, traction, and ease of manufacturing. The aim of this paper is to strategize cooling system of rear-mounted engine of a small gasoline car. Radiator and cooling fan packaged close to engine at rear of the car for simple packaging. Efficient thermal management ensured by robust overheat protection stratagem using EMS software. DFSS, a disciplined problem prevention approach that helps in achieving the most optimum design solution and provides improved and cost effective quality products; is used to finalize an optimum design based on the analysis of the various tests carried out as per DOE [1]. This paper is about designing a distinctive cooling system of a car having rear-mounted engine with rear radiator but front mounted HVAC system [2].

As the automobile industry in India is growing fast and competitive, there is a need to design the vehicle and its parts at most cost effective. This paper gives the details of design optimization and cost effective methodology followed to develop a Single Stalk Combination Switch, without degrading the end user delight. This paper describes various design criteria affecting the combination switch design.

An automotive radiator cooling fan has been observed to be an important noise source in a vehicle and with increasing noise refinements, the need for a quieter but effective fan is of utmost importance. Although some empirical prediction techniques are present in literature, they are not sufficiently accurate and cannot give a detailed view of the entire noise spectrum and the various noise prone zones. Hence the need for highly accurate Computational Fluid Dynamics (CFD) study is essential to be able to resolve the minute acoustic stress. Large Eddy Simulation technique in CFD is used to resolve the minute scales of motion in the flow as the sound pressures simulated are very small compared to system level pressures and require immense accuracy. Detailed mesh dependency and Y+ studies are conducted to implement higher accuracy as well as keep mesh requirements within computationally feasible zone.