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An agricultural tractor is often modified for special farming applications such as horticulture where the standard design is not suitable or accessible. In such cases, farm equipment manufacturers are demanded frugal and cost effect Engineered farming solutions. One such design is the innovative High Ground Clearance Tractor (HGCT) kit offered to increase the Tractor height without damaging the crop during farming operations. In this paper, the author proposes a durability assessment method to evaluate the HGCT kit attachments to meet the durability criteria. Road load data acquisition is done to measure the acceleration and strain levels for various horticulture operations such as tillage, spraying and transportation. Actual operating conditions are simulated with the help of four poster durability setups inside the lab which helps to reduce the field testing for design iterations.

The commercial vehicles market is dominated by manual transmission, due to lower ownership cost. Generally, commercial vehicles are used in large numbers by the fleet owners. The transmission endurance life is very important to a vehicle owner. On the other hand, driver fatigue can be reduced with a smooth gear change process. The gear change process in a manual transmission is carried out with the help of the synchronizer pack. The crucial function of a synchronizer pack in an automotive transmission is to match the speed of the target gear for smooth gear shifting. In a transmission, the loose and the weakest part is the synchronizer ring. The failure of the synchronizer affects smooth gear shifting and it also affects the endurance life of the transmission. The synchronizer ring can fail due to poor structural strength, synchronizer liner wear, synchronizer liner burning, etc.

Customers expect more advanced features and comfort in electric vehicles. It is challenging for NVH engineers to reduce the vibration levels to a great extent in the vehicle without adding cost and weight. This paper focuses on reducing the tactile vibration in electric vehicle when AC is switched ON. Vibration levels were not acceptable and modulating in nature on the test vehicle. Electric compressor is used for cabin cooling and battery cooling in the vehicle. Compressor is connected to body with the help of isolators. Depending upon cooling load, the compressor operates between 1000 rpm and 8000 rpm. The 1st order vibration of compressor was dominant on tactile locations at all the compressor speeds. Vibration levels on steering wheel were improved by 10 dB on reducing the dynamic stiffness of isolators. To reduce the transfer of compressor vibration further, isolators are provided on HVAC line connection on body and mufflers are provided in suction and discharge line.

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.

Automotive steel wheel is a critical component for human safety. For validating steel wheel various tests will be performed at component and vehicle level. Cornering test performed at vehicle level is one of the tests, where wheel will be validated for high cornering loads. Cornering test performed at vehicle level consists of three different events i.e., rotations of vehicle in track1, rotations of vehicle track 2 and rotations of vehicle in track3. As wheel will experience different loading in each of the events of cornering test, correlating the virtual Finite Element Analysis (FEA) with physical test is quite challenging. If in FEA we can predict the damage and life very near to the physical validation, we can create a safe wheel for high cornering loads without any test concerns. Vent hole shape and Hat depth are two important aspects in wheel disc design. Vent hole shape and size will influence the heat dissipation of braking.

Multidisciplinary Design Optimization (MDO) of an automobile body structure is a challenging task as it involves multiple, often conflicting requirements of safety, durability & NVH. Conventionally MDO process requires running large number of design of experiments (DOE) to explore the full design space and to build response surface for optimization. As the safety simulations are highly nonlinear in nature, they typically require significant amount of computational time and resources. Hence the conventional MDO approach is too expensive if too many design variables are simultaneously considered. In this paper, an alternative approach using Equivalent Static Load (ESL) method has been suggested for MDO which is quicker & accurate. The basic idea of the Equivalent Static Load-Method (ESL) is to divide the original nonlinear dynamic optimization problem into an iterative linear optimization and nonlinear analysis process.

Synchronizers are the most critical parts of a manual transmission. There are classical calculations available for the synchronizer design and studies are available for the normal functioning of synchronizer rings which describes how the synchronizer behaves in the event of gear shifting. The objective of this study is to describe the synchronizer behavior when synchronizers are not functional, i.e., in other gear engaged condition and the rings are free. This study describes the failure mechanism of the unused synchronizer rings which are moving freely in the packaging space. The findings of this synchronizer design cannot be limited only for synchronizer performance and standard durability calculations. To ensure proper function of synchronizer rings and to achieve the required life the external parameters like clearances, lubrication, clutch design for dampening torsional vibration from the engine are to be considered.

Automotive manufacturers are concerned about the safety of its customers. Safety critical components like wheel hub are designed considering the severe loads generated from various customer usage patterns. Accelerated tests, which are derived from Real World Usage Patterns (RWUP), are conducted at vehicle level to ensure the wheel hub meet the durability targets. Load and strain measurement are done to understand the critical lateral loading undergone by the wheel hub. Measured data is synthesized to drive the duty cycle. Finite Element (FE) Analysis of Wheel end is performed at module level considering measured loads to capture the exact load path in physical test. Simulation results are compared with the measured strain for validating the FE analysis procedure. FE analysis was repeated for different wheel hub designs, combinations of different flange radius (R) and flange width (t), to understand the effect of the two critical dimensions on wheel hub durability.

Vibrational fatigue is a metal fatigue caused by the forced vibrations which are purely random in nature. The phenomenon is predominantly important for the components/systems which are subjected to extreme vibration during its operation. In a vehicle, an engine is the main source of vibration. The vibrational fatigue, therefore, plays a key role in the deterioration of engine mounted components. Multiple test standards and methodologies are available for validating engine mounted parts of an automobile. These might not be appropriate in the case of an off- road vehicle as the vibrational exposure of engine mounted components of an off-road vehicle is entirely different. In the case of an off-road vehicle, the engine mounted components are subjected to a comparatively higher level of vibration for a longer duration of time as compared to the passenger cars.

The traditional approach of engine thermal behavior of engine during startup has largely been dependent on experimental studies and high fidelity simulations like CFD. However, these techniques require considerable effort, cost and time. The low fidelity simulations validated with experimental results are becoming more popular due to their ease in handling the several parameters such as cost effectiveness and quick predictive results. A four point mass model of engine thermal behavior during cold start has been developed to study the engine warm up temperature behavior. The four point mass model considers the lumped mass of coolant, mass of engine directly associated with the coolant, mass of engine oil and mass of engine directly associated with the engine oil. The advantage of four point model is to predict the coolant temperature as well as lubricant temperature during the transient warm up cycle of the engine.

Heat exchangers are thermoregulatory system of an automotive air conditioning system. They are responsible for heat exchange between refrigerant and air. Sizing of the heat exchanger becomes critical to achieve the required thermal performance. In the present work, the behavior of heat exchanger with respect to change in size is studied in detail by developing a scaling model. The limited experiments have been conducted for 3 different condensers. Commercially available 1D tool GT Suite is used for simulations. The heat exchangers are modeled using COOL3D module of GT Suite. The experimental thermal capacities of heat exchanger are compared with the simulated values. A good agreement up to ±2.3% is found between the experiments and simulations. Then developed scaling model in GT Suite is used for predicting the thermal behavior of heat exchangers by changing the size of the heat exchanger. Scaled thermal capacities of each model is compared with the corresponding experimental results.

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.

The prime focus of automotive industries in recent times is to improve the energy efficiency of automotive subsystem and system as whole. Harvesting the waste energy and averaging the peak thermal loads using thermal energy storage (TES) materials and devices can help to improve the energy efficiency of automotive system and sub-system. The phase change materials (PCM) well suit the requirement of energy storage/release according to demand requirement. One such example of TES using PCM is extended automotive cabin comfort during vehicle idling and city traffics including start/stop of the engine at traffic stops. PCM as TES poses high density and capacity in thermal energy storage and release. It is due to latent heat absorption and release during phase change. Generally the latent heat of a material compare to it sensible heat is much higher, almost an order of 2. For example, latent heat of ice is almost 160 times higher than sensible heat for a kelvin temperature rise of ice.

In vehicle Front End Flow (FEF) analysis, the basic objective is to predict the mass flow/velocity of air at radiator inlet with constant fan rotation. In general, the Multiple Reference Frame (MRF) model is used to model the fan. The flow velocity distribution at radiator inlet due to fan rotation should be uniform in circumferential direction whereas, it should vary in radial direction depending upon the blade geometry. However, the drawback with MRF model is that, it gives higher velocities near radiator inlet at regions corresponding to the fan blades and lower velocities at other regions, which is not realistic. This issue is more predominant when the vehicle is at low speeds or when radiator is placed at mid or back of the vehicle or the fan is having less number of blades. In order to nullify this uneven velocity distribution at radiator inlet, Mixing Plane (MP) approach was used in addition to the MRF model.

Scooter segment growth is tremendously increasing in India. The increased competition challenges automotive manufacturers to deliver the high quality and high reliable product to the market. Higher reliability involves increased durability testing which involves time and cost. Stress testing a part of durability is initially conducted on prototype vehicles for structural design validation and then later on production units to ensure its structural integrity. The obtained data from the tests can be used for future structural design improvements. Scooters with small tires, suspension limitations transfers more loads to structure, challenges engineers to design robust structure without compromising on weight much. It is necessary to look at Real World Usage Pattern (RWUP) and to create a stress life cycle block for simulation of accelerated testing, thereby optimizing the testing time and the development costs.

The present work is concerned with the design of an optimum air intake system for a single cylinder reciprocating diesel engine. It is a well known fact that air flow rates of a naturally aspirated engine are sensitive to the geometrical dimensions of the pipes that connect the engine to the atmosphere. Hence, tuning intake system dimensions for optimum airflow rates is of great importance. In this scenario simulation tools can be useful for the optimization of intake system. The one dimensional simulation tool AVL BOOST is used to predict air flow rates with different combinations of connecting hose diameters and lengths. Subsequently air flow rates are measured with selected clean hoses on an engine steady state test bench. It is found in the initial tests that the lengths and diameters of optimum hoses deviate from the AVL BOOST predicted optimum geometric dimensions.

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.

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.