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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.

Whole Body Vibration (WBV) of tractors was measured on different surfaces in real world usage pattern of Indian customers on tractors of various capacities. Vibration levels were measured at the interface of the seat and the operator, on the seat base/floor and on the head. The mean weighted Root Mean Square (RMS) values along the different axes, the vector sum of weighted RMS values along the three orthogonal axes, the crest factor, Vibration Dose Value (VDV) and 8 h exposure levels were calculated according to ISO 2631-1. In addition to the above parameters, the transmissibility between the seat base and the seat interface (SEAT) and between the seat interface and the operator head (TR) were also calculated. Finally, these parameters were correlated with the subjective feel of customers which was captured through suitable questionnaires. It is observed that the Indian tractor operators are exposed to WBV that exceeds the cautionary boundaries set in place by the ISO 2631-1.

In the current era, vehicle manufacturers focus has increased towards passenger comfort and one of the key areas is NVH. Vehicle level NVH targets are cascaded to component level for obtaining better refinement in cabin. One such performance attribute is sloshing noise of urea in diesel vehicles. Migration from BS4 to BS6.2 norms demand complex technological changes to automobile manufacturers to add extra components to the vehicles which is a big challenge in identifying the locations at critical stage of the project phase. In one of the developments of mid SUV category vehicle, sloshing noise from urea tank is perceived as objectionable during low-speed braking and while passing over speed breakers. This paper addresses the measurement conditions of sloshing noise and its evaluation procedure to quantify the sloshing noise at vehicle level. The sloshing noise is perceived in the frequency band of 50 to 1000 Hz.

In today's competitive automobile market, customers have become more sensitive towards NVH behavior of the vehicle than ever. The noise generated by gear rattle is one of the main contributors towards customer's overall NVH perception. This paper adopts a model based design approach towards gear rattle phenomenon to predict the tendency of gear rattle at a very early stage of design. This up-front understanding of gear rattle will potentially reduce the expensive design changes and iterations at later stages. A single unloaded gear pair is modeled in AMESim software, which is then extended to the complete gearbox in neutral condition. The sensitivity of rattle index for different input parameters is studied. Analysis on uncertainty propagation is carried out to find the rattle index distribution for Gaussian variation of input parameters. A novel rattle index based on Jerk is proposed and compared with the existing index.

Sound package material selection plays a vital role in maintaining passenger comfort by suppressing noise inside cabin. Sound package development in static condition minimizes the extrinsic variables which influence the measurements. The consideration of static condition favors simulation and its correlation with test data. Once correlation is achieved, simulation inputs are used for further optimization and improvements. Noise control can be done in three levels by working either on source, path or receiver. In automobiles, there are many sources of noise such as engine, tire and wind. This topic deals with quantification of various transfer paths between source and receiver location using Power Based Noise Reduction (PBNR) method. This methodology is used in both simulation and testing along with its overall scope for improvement. It is best to quantify path strength in terms of energy levels instead of mere amplitude due to its independency on external test conditions.

This paper presents a simulation for the gear shift process of a manual transmission, implemented using a library function. All the subsystem (i.e. synchronizer and the shift system) are correlated to generate a gear shift curve for optimum shift ability prediction of a manual transmission. A 5-speed manual transmission is used as an example in the paper to illustrate the simulation, co-relation and the validation of the gear shift performance curve on the vehicle. The dynamic behavior of the shift system and synchronizer in engaging and disengaging the gear is simulated through the gear shift characteristics to generate the shift rail's ramp profile. The synchronizer travel is co-related with the shift rail ramp profile to get a negative force after synchronization is over. The profile indicates the role of the detent ball diameter, radius on the shift rail ramp's profile etc and how it affects synchronizer force over the shift rail travel.

The demand of gear shift quality in vehicles has increased considerably in the past few years. The gear shift is the key interface between driver and vehicle transmission. The essential criterions for the operating quality of the gear shift is the operating force and feel on the gear shift knob at each stage of gear shift, starting from start of gear shift to the end of gear shift. This paper deals with techniques to reduce secondary force due to synchronizer sleeve hitting on dog ring at the end of gear shift which is also known as Double Bump. The double bump ratio should be less than 0.4 to achieve the best in class shift feel for passenger car segment. Normal driver will not feel if double bump ratio is less than 0.6. Inertia mass mounted on shift system of manual transmission helps to generate momentum at the end of gear shift to nullify the double bump force.

BSR (Buzz, Squeak and Rattle) is one of the oldest concerns in automobiles which directly reflect the build, assembly and manufacturing quality of a vehicle. In a cabin all the areas where there is relative motion between two components, such as trims, instrument panel and seats, are prone to squeak. This paper explains the study of seat squeak measurement and diagnosis which is a major concern for one of the products which is already in the market. Since squeak is a friction induced non stationary phenomenon, lot of effort was required to generate squeak in both component as well as vehicle level. At component level, electrodynamic shaker was extensively used for generation of squeak signals. In Vehicle level, driving through different road patterns, pave track and forced excitation on four posters are performed for generation of squeak signals. In this paper usage of wavelet and Zwikker loudness are explained for the diagnosis of seat squeak to identify the problematic frequencies.

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.

Material selection is based on Process such as forging, die-casting, machining, welding and injection moulding and application as type of load for Knife Edges and Pivots, to minimize Thermal Distortion, for Safe Pressure Vessels, Stiff, High Damping Materials, etc. In order for gears to achieve their intended performance, durability and reliability, the selection of a suitable gear material is very important. High load capacity requires a tough, hard material that is difficult to machine; whereas high precision favors materials that are easy to machine and therefore have lower strength and hardness ratings. Gears are made of variety of materials depending on the requirement of the machine. They are made of plastic, steel, wood, cast iron, aluminum, brass, powdered metal, magnetic alloys and many others. The gear designer and user face a myriad of choices. The final selection should be based upon an understanding of material properties and application requirements.

In the automobile industry, the door closing effort spells out the engineering and quality of the vehicle. After the visual impact a vehicle has on the customer, the doors are most likely the very first part of the vehicle he/she encounters, to enter and exit the vehicle. One of the customer’s very first impressions about the quality of the car is given by the behavior of the doors when opening and closing, the swinging velocity and the energy that is required to obtain a full latching that the door makes when closed by the user. Door closing effort gives an indication of how good or bad the vehicle is engineered. The purpose of this paper is to propose modifications in the door system which help in reduction of door closing effort or velocity by two different methods, EZ Slam Door and Bungee Rope. In this paper, parameters like hinge friction, hinge axis inclination, sealing, latch and air bind effect are analyzed which affect door closing effort.

Airbags play a vital role in occupant protection during a crash event. Apart from the crash test the airbags have to additionally meet the requirements of the ECE R 12 headform impact test with Driver's Airbag (DAB) located in the steering wheel being deployed and the ECE R21 headform impact test for Passenger Airbag (PAB) in undeployed condition. Improper location of the PAB module below the Instrument Panel, the design of the air bag housing and the Instrument Panel are some of the factors that could lead to non compliance of the components of the uninflated PAB. The paper deals with the investigation conducted for compliance of the PAB to ECE R 21 with the uninflated air bag in meeting the requirements of 80 g at 19.3 km/h by proper location, changes to the design of the PAB cover, air bag housing brackets, etc.

Plenum is the part located between the front windshield and the bonnet of an automobile . It is primarily used as an air inlet to the HVAC during fresh air mode operation. It’s secondary functions include water drainage, aesthetic cover to hide the gap between windshield to bonnet, concealing wiper motors and mechanisms etc. The plenum consists mainly two sub parts viz. upper plenum and lower plenum. Conventional plenum design which is found in majority of global OEMs employ a plastic upper plenum and a metal lower plenum which spans across the entire width of engine compartment. This conventional lower plenum is bulky, consumes more packaging space and has more weight. In this paper, we propose a novel design for the plenum lower to overcome above mentioned limitations of the conventional design. This novel design employs a dry and wet box concept for its working and is made up of complete plastic material.

Globally all OEMs are moving towards electric vehicle to reduce emission and fuel cost. Customers expect highest level of refinement and sophistication in electric vehicle. At present, the customers are sensitive to high pitched tonal noise produced by electric powertrain which gives a lot of challenges to NVH engineers to arrive at a cost-effective solution in less span of time. Higher structure borne tonal noise is perceived in electric vehicle at the vehicle speeds of ~ 28 kmph, 45 kmph and 85 kmph. The test vehicle is front wheel drive compact SUV powered by motor in the front. The electric drive unit is connected to cradle and subframe with help of three mounts. Transfer path analysis (TPA) using blocked forces method is carried out to identify the exact forces of the electric drive unit entering the mounts. Powertrain mount is characterized by applying the predicted forces and dynamic stiffness at problematic frequency is measured.

For ensuring environmental safety, strong emphasis on CO2 pollution reduction is mandated which led to evolution of miller cycle engines. However, the inherent Miller engine characteristic is the lower volumetric efficiency when compared to otto engines because of which small turbo chargers with variable geometry turbines are used to induct air into the engine. With miller engine and VGT turbo charger combination arises the challenges of charge controllability because of lower inertia and reduced vane control area. With conventional turbo charger control methods, the response time is slow thereby leading to turbo lag or severe over boosting, this is overcome by accurate engine modelling and using the same as input for charger control.

The paper talks about the migration phenomenon that is observed in gears. The phenomenon discussed here is that observed on hypoid gears which due to their high spiral angles cause the issue to be more sensitive, but the analogy to other gears is applicable. Mahindra manufactures hypoid gear sets for its axles in-house that go on a wide range of its products; with performance benefits also come the stringent quality requirements for hypoid gear sets. Migration is the phenomenon that causes the furling or unfurling of individual gear teeth with respect to each other. This in effect causes the circular tooth spacing between two teeth to become non-uniform. This has a direct effect on the performance of the mated gear set.

In automotive market, with competitive car prices, build quality of a car will be a major distinguishing factor. Consumer's need for acoustic comfort has evolved from the removal of annoying noises to perceived sound quality. Operational sounds from electromechanical systems like sunroof system, window regulator, door lock system, HVAC etc. directly interact with users’ senses. The perceived acoustics comfort of these sounds are direct indicators of vehicle character and can influence customer’s buying decision. With the reduction in product development time and stringent cost constraints, a proper structured target setting methodology to benchmark & evaluate these operational sounds is crucial. In this paper, such a target setting methodology is proposed and discussed for operational sound quality evaluation. Electromechanical noises from various vehicles are measured using binaural head measurement system.

Transmission quill gears are hot forged steel parts often used in constant mesh manual transmissions. The quill gear, which helps to transmit the power from input drive shaft to output shaft through driving gears. It’s having external teeth which is positively engaged with driving gear and sleeve. During gear selection sleeve take load from input shaft and transmit to driven gear. Quill gear directly engaged with driving gears on outer surface and bearing in inner surface which needs to have high strength and durability. These properties can be improved by carburization heat treatment in existing design such processes can lead to increased costs. We have developed quill gear through powder metallurgical process and then cooled rapidly in the furnace to get high strength and wear properties. Material composition are optimized to suit for sinter hardening process conditions.

Usually conventional iterative methods of optimization will consume more time to optimize the given design. Mostly, it becomes very difficult if multiple loads are acting on the structure contradicting each other. CAE based optimization technique becomes more useful in such cases to optimize the given design and achieve weight reduction. Optimization methods offers guidance to expedite solutions, resulting in a substantial reduction in product development time. Nowadays, optimization became inevitable part among the virtual validation processes of design in industries. A wide range of optimization methods have been effectively employed in the design of tractor components, especially mounting brackets, chassis and skid housing for the development of off-road vehicle. Based on the design stage, various optimization techniques were followed i.e. Topology, size and shape. Depending upon the available analysis time & Design freedom, determines the type of optimization approach to be used.

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.