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For the thermal management of an automobile, the induced airflow becomes necessary to enable the sufficient heat transfer with ambient. In this way, the components work within the designed temperature limit. It is the engine-cooling fan that enables the induced airflow. There are two types of engine-cooling fan, one that is driven by engine itself and the other one is electrically driven. Due to ease in handling, reduced power consumption, improved emission condition, electrically operated fan is becoming increasingly popular compared to engine driven fan. The prime mover for electric engine cooling fan is DC motor. Malfunction of DC motor due to overheating will lead to engine over heat, Poor HVAC performance, overheating of other critical components in engine bay. Based upon the real world driving condition, 1D transient thermal model of engine cooling fan motor is developed. This transient model is able to predict the temperature of rotor and casing with and without holes.

A competitive market and shrinking product development cycle have forced automotive companies to move from conventional testing methods to virtual simulation techniques. Virtual durability simulation of any component requires determination of loads acting on the structure when tested on the proving ground. In conventional method wheel force transducers are used to extract loads at wheel center. Extracted wheel center forces are used to derive component loads through multi-body simulation. Another conventional approach is to use force transducers mounted directly on the component joineries where load needs to be extracted. Both the methods are costly and time-consuming. Sometimes it is not feasible to place a load cell in the system to measure hard point loads because of its complexities. In that case, it would be advantageous to use structure itself as a load transducer by strain gauging the component and use those strain values to extract hard point loads in virtual simulation.

Wheel rim is one of the most critical safety parts in a vehicle. Strength in cornering loading is one of the most important durability test requirements for automotive steel wheel rim apart from other loading conditions like vertical and impact loads. Based on the category of vehicle and customer usage pattern, the accelerated cornering test is derived for testing steel wheel rims. The simulation and certification of steel wheel rim for the required dynamic durability testing requirement involves many steps ranging from acceptance criteria derivation to reliably addressing known potential failure zones in steel wheel rims. Nave radius and crown are sensitive to cornering loads, given the pitch circle diameter at the concept stage, the known effects of these key parameters are determined from DOE and used as reliable indicators to arrive at the shape and section of the steel wheel rim.

Aerodynamic simulation using commercial CFD (Computational Fluid Dynamics) codes is now an integral part of the vehicle design process. Aerodynamic prediction and vehicle development program runs in parallel. This requires a good agreement between experimental measurements and CFD prediction of aerodynamic behavior of a vehicle. The comparison between experimental and simulation results show differences, as it may not be possible to replicate effect of all the wind tunnel parameters in the simulation. This paper presents the details of aerodynamic simulation process of a Crossover and its validation with the experimental results available from the wind tunnel tests. The results are compared for different configurations such as- closing the grille openings, removing the rearview mirror, adding ski-rack and using different tyres. This study also includes the effect of different wind speeds and yaw angles on the coefficient of drag.

Roll-over protective structures (ROPS) are safety devices which provide a safe environment for the tractor operator during an accidental rollover. The ROPS must pass either a dynamic or static testing sequence or both in accordance with SAE J2194. These tests examine the performance of ROPS to withstand a sequence of loadings and to see if the clearance zone around the operator station remains intact in the event of an overturn. In order to shorten the time and reduce the cost of new product development, non-linear finite element (FE) analysis is practiced routinely in ROPS design and development. By correlating the simulation with the results obtained from testing a prototype validates the CAE model and its assumptions. The FE analysis follows SAE procedure J2194 for testing the performance of ROPS. The Abaqus version 6.12 finite element software is used in the analysis, which includes the geometric, contact and material nonlinear options.

In the present age automotive manufacturers are putting their effort to reduce product cycle time and product cost. This has been possible with the help of Computer Aided Engineering (CAE). CAE is playing vital role in design and develop of new products as well as up gradation of existing one to meet new safety regulations and customer requirements. It has become increasingly accepted that use of well-developed, CAE models present the best approach for upfront prediction of vehicle behaviour. The ability to simply predict trends is no longer acceptable. Meaningful results can be derived, and projections made, from the CAE model, only if the CAE results are correlated against physical tests. Correlation between Simulation and Physical test is key, to build confidence on product development with virtual validation. This paper discusses the correlation between the CAE and Physical Test for offset deformable barrier crash for 4 Wheel Drive (4WD) Sports Utility Vehicle (SUV) vehicle.

Validation of vehicle structure is at the core of reduction of product development time. Robust and accelerated validation becomes an important task. In service the vehicle is subjected to variable loads. These act upon the components that originate from road roughness, manoeuvres and powertrain loads. Majority of the body in white and chassis structural failures are caused due to vertical loading. Measured road load data in test track have variable amplitude histories. These histories often contain a large percentage of small amplitude cycles which are non damaging. This paper describes a systematic approach to derive the compressed load cycle from the measured road load data in order to produce representative and meaningful yet economical load cycle for fatigue simulation. In-house flow was developed to derive the compressed load time history.

The scope of the project is to achieve SUV structural performance improvement to meet the offset frontal crash safety requirements as per ECE R 94 Regulation by design modifications in different Sub-systems of the vehicle structure suggested with the help of CAE crash simulations. The study can be classified in four main phases mentioned below. The first phase of the development is to conduct a crash test and CAE simulation for the baseline design. The second phase includes correlation activity among baseline test and CAE. The third phase is to achieve improvement by vehicle structure design modifications and new parts in chassis and BIW guided with CAE simulations and design iterations. Finally the forth phase deals with validation of new crashworthy vehicle design by last crash test.

A differential casing is one of the important elements in the vehicle power train, whose objective is to house differential gears and take different loads coming from these gears. The function of a differential is to drive a pair of wheels while allowing them to rotate at different speeds. While taking a turn, the outer wheel needs to travel more compared to the inner wheel. This is possible due to the differential which rotates them at different speeds. This Paper highlights a simplified methodology to capture the differential casing failure and to resolve the same. The methodology adopted was then correlated with the test measurements to increase the confidence. During physical tests, strains are measured at different orientations of the differential casing and correlated with simulation results.

In the new product design, meeting customer requirements, process alignment, timely execution and successful implementation plays a critical role. Six sigma methodology is a disciplined, standardized methodology supported by analytical tools to meet the quality and functional targets. An engine cradle or sub-frame is the principal load carrying member in a monocoque vehicle construction. It is extensively used to (i) provide structural support and retention of power train, suspension control arms, stabilizer bar, and steering rack mounting features (ii) to isolate the high frequency vibrations of engine and suspension from the remaining structures (iii) to absorb and transmit the impact forces during frontal crash. This paper attempts to explain (i) the various DFSS-DMADV techniques used during the engine cradle design and development (ii) correlation between the cradle stiffness simulation and test measurement values (iii) cradle NVH test results.

The development of interior fittings of passenger car to minimize the injuries to the head of the occupants requires mandatory compliance to the regulations in Europe and USA. In European regulation ECE R21 and similarly in FMVSS 201 the test on the instrument panel area suffices. The FMVSS 201u requirements in USA require also a free motion headform to be impacted on additional areas of the A-Pillar trim, sun visors, grab handles, and seat belt upper anchorage points of the B-Pillar too. Free Motion Headform Impactors (FMHI) are costly equipment. The FMVSS 201u [1] test is not conducted by any test agency in India as yet. Paper deals with the development of the head form impactor to fire the headform at angular positions in the vehicle and the test results have enabled the development of the vehicle interiors to enhance the safety of vehicles in crash situations.

This paper takes a review of fretting phenomenon on splines of the engaging gears and corresponding splines on shaft of automotive transmission and how it leads to failure of other components in the gearbox. Fretting is a special wear process which occurs at the contact area of two mating metal surfaces when subject to minute relative oscillating motion under vibration. In automotive gearbox, which is subjected to torsional vibrations of the powertrain, the splines of engaging gears and corresponding shaft may experience fretting, especially when the subject gear pair is not engaged. The wear debris formed under fretting process when oxidizes becomes very hard and more abrasive than base metal. These oxidized wear particles when comes in mesh contact with nearby components like bearings, gears etc. may damage these parts during operation and eventually lead to failure.

In current competitive environment automobile industry is under heavy pressure to reduce time to market. First time right design is an important aspect to achieve the time and cost targets. CAE is a tool which helps designer to come up with first time right design. This also calls for high degree of confidence in CAE simulation results which can only be achieved by undertaking correlation exercises. In automobiles most of the structures are subjected to vibration from dynamic loads. All the dynamic road loads are random in nature and can be very easily expressed in terms of power spectral density functions. In the current scenario structural durability of the parts subjected to vibration is done partially through modal performance and partially though frequency response analysis. The only question that arises is what amplitude to use at what frequency and how to map all the accelerated tests dynamic load frequency spectrum to simulation domain.

The customer perception about the door slam noise and its feel would indicate the brand image of the car. In this paper the authors have made an effort to improve the door slam noise quality of the vehicle, which is currently in production. This paper describes the probable areas in the door to improve the slam noise quality by attempting modifications in the door design factors, such as door alignments, door panel stiffness, door trims, window glass rattle, latch striker alignment, door seals, air extractor. Since the door closing event is a transient phenomenon, it requires special tools such as wavelet transforms, Zwicker loudness to understand the slam events precisely. Subjective jury evaluations have been conducted to understand the effect of these modifications and rank the modifications based on their contributions to the door slam quality.

In commercial vehicles which generally have large capacity fuel tank, sloshing of fuel and its effect on the tank structure is very important aspect during fuel tank design. Dynamic pressures exerted by the fuel on baffles, end plates and tank shell during sloshing can lead to structural failures and fuel leakage problems. Fluid structure interaction simulation of automotive fuel tank sloshing and its correlation with physical test is demonstrated in this study. During physical sloshing test of 350 L fuel tank, cracks were observed on center baffle and spot weld failures developed on fuel tank shell. Same sloshing test was simulated for one sloshing cycle using fluid structure interaction approach in LS Dyna explicit FE solver. Water was used instead of fuel. Mesh free Smoothed Particle Hydrodynamics (SPH) method is used to represent water as it requires less computational time as compared to Eulerian or ALE method.

In automotive industry, design of vehicle to end customer with proper ergonomics and balancing the design is always a challenge, for which an accurate prediction of postures are needed. Several studies have used Digital Human Models (DHM) to examine specific movements related to ingress and egress by translating complex tasks, like vehicle egress through DHMs. This requires an in-depth analysis of users to ensure such models reflect the range of abilities inherent to the population. Designers are increasingly using digital mock-ups of the built environment using DHMs as a means to reduce costs and speed-up the “time-to-market” of products. DHMs can help to improve the ergonomics of a product but must be representative of actual users.

Drive cycles have been an integral part of emission tests and virtual simulations for decades. A drive cycle is a representation of running behavior of a typical vehicle, involving the drive pattern, road characteristics and traffic characteristics. Drive cycles are typically used to assess vehicle performance parameters, perform system sizing and perform accelerated testing on a test bed or a virtual test environment, hence reducing the expenses on road tests. This study is an attempt to design a relatively robust process to generate a real world drive cycle. It is based on a Six Sigma design approach which utilizes data acquired from real world road trials. It explicitly describes the process of generating a drive cycle which closely represents the real world road drive scenario. The study also focuses on validation of the process by simulation and statistical analysis.

Reducing material wherever there is a possibility in automobile industry is inevitable for weight and cost saving. This paper explains about the possibilities of optimizing the material composition of automotive Headliners (also called as Roof liners) without affecting the performance and safety criteria. In this paper, we are targeting at optimizing the individual constituents of a composite Headliner. A conventional Headliner comprises of many sandwich layers of which PU foam shares the major percentage of the composition contributing to 80% of the Headliner thickness. In this paper, we are discussing about the optimization done in Headliner sandwich constituents without affecting the core performance parameters of headliner such as curtain airbag deployment, ergonomic regulations, drop test etc. By incorporating this change, without significant changes in other layers, overall weight reduction of ~24% and overall cost reduction of ~24% is achieved.

A vehicle drifts due to several reasons from its intended straight path even in the case of no steering input. Vehicle pull is a condition where the driver must apply a constant correction torque to the steering wheel to maintain a straight-line course of the vehicle. This paper presents an investigation study into the characteristics of a vehicle experiencing steering drift. The aim of the work is to study vehicle stability and the causes of vehicle drift/pull during straight line to minimize vehicle pull level and hence optimize safety measures. A wobble in the steering wheel feels like the steering wheel is shaking to the left and right. This may get worse, if speed increases. This paper focuses on modelling and evaluating effects of suspension parameters, differential friction, brake drag variation, Unbalanced mass in the wheel assembly and C.G. location of the vehicle under multibody dynamic simulation environment.

In-vehicle displays such as an instrument cluster in a vehicle provide vital information to the user. The information in terms of displays and tell-tales needs to be perceived by the user with minimal glance during driving. Drivers must recognize the condition of the vehicle and the state of its surroundings through primarily visual means. Drivers then process this in the brain, draw on their memory to identify problem situations, decide on a plan of action and execute it in order to avoid an accident. There are visual hindrances seen in real world scenario such as obscuration, reflection and glare on the instrument cluster which prevents the vital information flow from vehicle to the driver. In order to ensure safety while driving, the instrument cluster or driver displays should be placed in an optimized location. This paper deals with how to achieve a visual hindrance free cluster position in a vehicle to protect the important information flow from the vehicle to the driver.