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In an electric vehicle, internal combustion engines are replaced by the electric motor. As a result, the signature of source vibration changes. The noise, vibration and harshness (NVH) issues are entirely different in electric vehicle (EV) compared to internal combustion engine (ICE) due to the change in source vibration. The outline of this paper is a comparative study of source vibration, the challenges to address various noise issues related to source vibration and the isolation methodology. A case study is presented to show the different methods of treatment required to mitigate source vibration issues during the electric vehicle development program. Keywords: Engine, Motor, vibration

Production variations of a heavy duty truck for its vibrations were measured and then analyzed through an Ishikawa diagram. Noise and Control factors of the truck idle shake were indentified. The major cause was found to be piece to piece variations of its power-train (PT) rubber mounts. To overcome the same, a new nominal level of the mount stiffness was sought based on minimization of a cost function related to vibration transmissibility and fatigue damage of the mounts under dynamic loadings. Physical prototypes of such mounts were proved to minimize the variations of the driver's seat shake at idling among various trucks of the same design. These learning's are useful for design of various subsystems or components to refine the full vehicle-Noise Vibration Harshness (NVH) at the robust design level.

The customer expectations in the passenger car market are predominantly in the areas of engine/vehicle performance along with NVH refinement. In addition, continuously evolving regulatory emission and crash norms with system cost considerations bring out multiple challenges on to design engineers. One of the vehicle systems that has its footprints on all of the above requirements is the engine air intake system. In this paper, using multidisciplinary approach we discuss the impact of air intake system design of a 3-cylinder gasoline engine on different attributes of customer requirements. The primary function of the air intake system is to provide filtered air to the engine. However, this paper explains how requirements like engine performance, NVH refinement, regulatory and styling, durability, servicing and system cost are affected by intake system design parameters.

The clutch is the connecting link between engine and the power train. It connects and disconnects the engine to the gearbox as per the wish of the driver. Clutch has a friction disc which acts like a fuse wire which wears in the process of the connection. This paper tries to calculate the clutch life analytically (In terms of Kms. run by vehicle), of automotive vehicles having manual transmission. As the clutch engages and disengages the engine to the gearbox, during this time due to slippage, energy is dissipated which results in the wear of the clutch disc. It calculates life based on the volumetric wear of the clutch disc and wear allowance available. The work done by other people in this domain include the empirical estimation of clutch life based on the past data, effect of the surface topography on the friction characteristics of the wet clutches, modeling of clutch housing and facing temperature for the estimation of the clutch life of a manual transmission etc.

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.

Steering column and steering wheel are critical safety components in vehicle interior environment. Steering system needs to be designed to absorb occupant impact energy in the event of crash thereby reducing the risk of injury to the occupant. This is more critical for non-airbag vehicle versions. To evaluate the steering system performance, Body block impact test is defined in IS11939 standard [1]. Nowadays for product development, CAE is being extensively used to reduce development cycle time and minimize number of prototypes required for physical validation. In order to design the steering system to meet the Body Block performance requirements, a detailed FE model of Body Block impactor is required. The static stiffness and moment of inertia of body block are defined in SAE J244a [2]. The reference data available in SAE J244a is not sufficient to develop a Body Block model that would represent the physical impactor.

The interior components of a passenger vehicle are designed to provide comfort and safety to its occupants. In the event of accident, vehicle interiors are primary source of injuries when occupants interact with them. Vehicle interiors consists of Instrument panel (IP), center console, seats and controls in front of seating position etc. Severity of the injuries depends on the energy dissipating characteristics, profiles, projections of different interior components. These are assessed by ECE R21 and IS12553 head form impact tests. To evaluate the Head form impact performance on Interior components, Computer Aided Engineering (CAE) simulations are extensively used during the vehicle development. In order to predict failure of plastic components and snap joints which might lead to expose sharp edges, it is critical to model plastic material and snap joint.

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.

The vehicle crash signature (here on referred as crash pulse) significantly affects occupant restraints system performance in frontal crash events. Restraints system optimization is usually undertaken in later phase of product development. This leads to sub-optimal configurations and performance, as no opportunity exists to tune vehicle structure and occupant package layouts. In concept phase of development, crash pulse characterization helps to map occupant package environment with available structure crush space and stiffness. The crash pulse slope, peaks, average values at discrete time intervals, can be tuned considering library of restraints parameters. This would help to derive an optimal occupant kinematics and occupant-restraints interaction in crash event. A case study has been explained in this paper to highlight the methodology.

Crank train torsional vibration is an important aspect for design and development of Powertrain for NVH refinement and durability. Crank train torsional vibration parameters like angular acceleration of flywheel or twist, depends upon various design parameters like geometry of crankshaft, mass of flywheel, stiffness of clutch, mass of pulley etc. It also depends upon engine operating conditions like engine speed, engine load, combustion peak pressure and combustion pressure variation etc. Most of these parameters are decided by engine power, torque, engine architecture and packaging constraints. Addition of torsional vibration damper (TVD), which works on the principle of tuned dynamic absorber, is commonly deployed design solution to control the torsional vibrations as well as stresses (to improve durability of crank train) induced in crank train assembly at specified modal frequency.

For sustainability, industries are now focusing on methodologies for Recycle, Reuse, Repair of a variety of industrial material. Cutting tools used in manufacturing of automobiles have therefore become a part of it. There are many ways in which cutting tools can be recycled. Be it by reshaping a used up throwaway type tool [1] or by redesigning a tool holder for the use of unused cutting edges [2]. An automobile part was redesigned for reuse of a used up tool [3]. By reforming, very large size grinding wheel used for crankshaft grinding can be reused after it gets smaller in diameter during crankshaft grinding operation [4]. This paper deals with two more implemented ideas to show that with a redesigned tool holder it was possible to reuse used up carbide inserts and significantly cut the manufacturing cost in addition to avoid manufacturing of new inserts and thus conserve natural resources.

Vehicle refinement from point of view reduction in its Noise, Vibrations and Harshness (NVH) affects customer’s buying decision and it also directly influences his/her driving experience on road at different speeds. Customer voice, however, indicates that a traditional process of developing design solutions is not aligned with the customers’ expectations. Traditionally the load cases for NVH development are focused only on quietness of passengers’ cabin at idling and in 3rd gear wide open throttle cruising on smooth roads. In reality, the Driver of a premium sedan car or a Sports Utility Vehicle (SUV) or a Compact Utility Vehicle (CUV) expects something different than merely the low sound pressure level inside the cabin. His/her driving pattern over a day plays a crucial role. A vehicle-owner wishes to balance various attributes of the in-cab sound and tactile vibrations at a time.

Vehicle aerodynamic design has a critical impact on fuel efficiency of the vehicle. Reducing aerodynamic wind resistance of the vehicle's exterior shape and reducing losses associated with requirements for engine compartment cooling through vehicle front openings plays key role in achieving desired aerodynamic efficiency. Today fairly large number of computational fluid dynamics (CFD) simulations are being performed during the vehicle aerodynamic design and development process and it is rapidly increasing day by day. Vehicle aerodynamic design and development process involves mainly aerodynamic shape development, aerodynamic optimizations of vehicle external components (side view mirror, spoilers, underbody shield etc.) and number of” what if studies during preliminary design process. Licensing costs of the available commercial CFD simulation solver has significant impact on product development cost when numbers of aerodynamic simulations expand.

EU directive 2005/64/EC on type approval of motor vehicles with respect to their Reusability, Recyclability and Recoverability ( RRR ) requires vehicle manufacturers to put in place the necessary arrangements and procedures for Parts, Materials and Weight (PMW ) data collection from full chain of supply. This is required to perform the calculations of recyclability rate and recoverability rate in line with ISO 22628. Commonly practiced data collection methodologies included spreadsheet and use of internationally available IT support system for collection of material data. Data complexity and prohibitive cost for using Internationally available IT Support systems like IMDS (International Material Data System) has led to the in-house development of IT enabled Solution customizing Siemens PLM software product (Team centre Enterprise) and SAP (SRM suite).

The recent vehicle development demands for electric powertrain as against conventional fuels engines. The electric powertrain offers advantages in terms of cleaner and quieter operations. In electric vehicle, the conventional engine is replaced by electric motor operated on batteries. Here, the conventional engine refers to those powered by diesel, petrol, CNG and some hybrid vehicles using fuel as primary source for power generation. Thus, the system design approach for mount also changes. At present, various approaches are being followed to mount electric powertrain like conventional pendulum type, with or without cradle, Common or different motor and electric box mountings etc. The electric powertrain differs from conventional powertrain in terms of weights, mass moment of inertia, torque, NVH requirements like Key in Key off, idling, low frequency vibrations etc. Thus conventional mount will not necessarily meet NVH requirements for Electric powertrains.

Severe air pollution in cities caused largely by vehicular emissions, which requires urgent remedial measures. As automobiles are indispensable modes of personal and public mobility, pre-emptive efforts are necessary to reduce the adverse effects arising from their operation. A significant improvement in air quality can be achieved through large-scale introduction of vehicles with extremely low emission such as hybrid-electric and zero emission vehicles. Range extension of electric vehicles (EVs) is also of utmost importance to alleviate the handicap of restricted mileage of purely plug-in EVs as compared to conventional vehicles. This paper presents development of a polymer electrolyte membrane (PEM) fuel cell stack used for the range extender electric vehicles. The Fuel cell stack for range extender vehicle operated in a dead end mode using hydrogen and air as open cathode.

Durability is an important indicator to measure the automobile quality and reliability. Automotive industry is striving to develop products having excellent performance to weight ratios and along with high safety standards. A successful product should have adequate robustness during normal customer operation and the ability to withstand high impact events without impairment of function or safety relevant damage. Road Load Data Acquisition (RLDA) along with efficient design and validation processes are, among others, critical factors for success in the automotive industry. Physical RLDA is expensive and time consuming, the prototype vehicles being costly and only available at a later stage in the vehicle development cycle. Component failures occurring on the proto test vehicles can prove to be a major setback, delaying the product launch by months. In order to overcome above challenge, this paper presents an innovative methodology to carry out Digital RLDA (dRLDA).

Recycle, Reuse, Repair is an established process for sustainability. There are many ways in which cutting tools can be recycled. Be it by reshaping a used up throwaway type tool [1] or by redesigning a tool holder for the use of unused cutting edges [2]. This paper explores the possibility of reuse of HSS drills that are used for making long oil holes in automobile parts like crankcase (cylinder block), cylinder head, crankshaft, etc. Design/manufacture of such drills is peculiar by virtue of their size and length and are also known as thick web high helix drills. Making of oil holes entails use of drills that are 500 to 600 mm long depending on the size of the component. In most of the long oil hole drilling operations, a limited portion of the drill is useable. This is because there is a possibility of fouling of the holding elements with guiding element, or with the part being drilled and the chance of accidental damage to part or machine.

The crankshaft is the component which transmits dynamic loads from cylinder pressure and inertial loads in engine operating conditions. Because of its crucial importance in functioning of engine and requisite to sustain high dynamic and torsional loading, crankshaft fatigue life is desired to be higher than the predicted engine operating life. Performance of the crank train in diesel engine applications largely depends on the components of its mass elastic system. Flywheel is one such component whose design affects the life of crankshaft. In the present study, the crank train comprising of torsional vibration damper, crankshaft and flywheel along with clutch cover is considered for analysis. Crankshaft dynamic simulation is performed with multi body dynamics technique, fatigue safety factors of crankshaft are calculated with dynamic loads under engine operating conditions.