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In automobiles, front axle assembly is a main load bearing member and houses steering linkages. Front axle assembly has two main parts namely axle beam and axle arm, interconnected by a kingpin. This kingpin allows the rotation of axle arm during steering events. To avoid metal to metal contact between axle arm and kingpin, bushes are housed on the top and bottom half of the axle arm & in axle beam. Due to radial load and steering rotation, as a weak member, bushes will wear out faster. This affects the proper functioning of steering mechanism. Hence, the bushes need to be evaluated prior to its implementation in vehicle. In general, bushes are evaluated using Pin-On-Disc test as a comparative study, but it does not simulate exact boundary conditions as in vehicle. Next option is vehicle level validation but leads to more testing time and cost. Hence, as an optimized solution, the same vehicle operating conditions can be replicated in component level testing.

In the modern automotive sector, durability and reliability are two terms of utmost importance and relevance. The ever improving standards and cut throat competition has led to customers expecting highly reliable products at low costs. Any product that fails within its useful life leads to customer dissatisfaction and affects the OEM’s reputation. To eradicate this, all automotive components undergo stringent validation protocol, either in proving ground or in lab. Multipurpose bracket is one of the most important and critical aggregate in the vehicle assembly. It encompasses various mounting components such as FUPD bracket, steering mounting bracket, front spring front bracket, cab mount bracket, cab tilt cylinder mounting bracket, front cross member, footstep bracket and bumper. All these components experience various degrees of vibration and fatigue during its running period.

One of the important factors strongly required by customers nowadays is lower noise and vibration in vehicle. In this paper the prime focus is made on the study of effect of driveline angles on the noise and vibration behavior in a 4X4 configuration commercial vehicle. The impact of propeller shaft angles in the transfer of driveline excitations to the transmission and the resulting noise and vibration is studied. An abnormal noise was perceived from transmission and the root cause was investigated for the same. These excitations were high due to the higher driveline angles as this was design requirement to maintain higher ground clearance. A two-stage approach was adopted to modify the effect (transmission) and cause (propeller shaft angle) there by reducing the abnormal noise and vibration perceived in the vehicle.

In the present scenario, delivering right product at the right time is very crucial in automotive sector. Today, most of the OEMs have started to produce FBS (Fully Build Solution) such as oil tankers, mining tippers and two-wheeler carriers based on the market requirements. During product development phase, all automotive components undergo stringent validation protocol either in on-road or laboratory which consumes most of the product development time. This project is focused on developing validation methodology for two-wheeler carrier structure (deck) of a commercial vehicle. For this, road load data were acquired in the typical routes of customers at different loading conditions. Roads were classified as either good or bad based on the axle acceleration. To shorten the test duration, actual road load data was compressed using strain based damage editing techniques. The spectrum and transmissibility of acceleration signals at the decks were analyzed to select a deck for validation.

This abstract work describes a method of data acquisition and validation procedure followed for a metal bumper used in commercial vehicle application. Covariance is considered as major phenomenon for repeatable measurements in proving ground data acquisition and it is to be maintained less than 0.05. In this project covariance of data acquisition is analyzed before physical simulation of acquired data. In addition to that, multiple testing conditions like uni-axial and bi-axial testing were carried out to attain the failure. PG data is used for bi-axial vibration test and conventional constant spectrum signal (CSD signal) is used for uni-axial vibration test. Target duration for uni-axial test (Z direction) was arrived using pseudo damage calculation. Strain gauges were installed in failure locations to compare PG data and rig data as well as to calculate strain life. Failures were simulated in bi-axial vibration test.

In the emerging commercial vehicle sector, it is very essential to give a product to customer, which is very reliable and less prone to the failures to make the product successful in the market. In order to make it possible, the product is to be validated to replicate the exact field conditions, where it is going to be operated. Lab testing plays a vital role in reproducing the field conditions in order to reduce the lead time in overall product life cycle development process. This paper deals with the design and fabrication of the steering column slip endurance test rig. This rig is capable of generating wear on the steering column splines coating which predominantly leads to failure of steering column. The data acquired from Proving Ground (PG) was analyzed and block cycles were generated with help of data analyzing tools.

Non air-conditioned buses constitute a major portion of public transportation facilities in many countries across the world. Inadequate cabin air circulation is a major cause of passenger discomfort in these buses. The aim of this study is to model the air flow pattern inside the passenger compartment of a bus and to establish the effect of solutions such as roof vents in improving the air circulation. RANS based CFD simulations with Shear Stress Transport (SST) turbulence model have been carried out using a commercial CFD solver. The CFD methodology has been verified by comparing results with experimentally validated LES simulation results available in literature. The vehicle model used in this study was the shell structure of a bus with an overall length of 7 m and a wheel base of 3.9 m. Simulations were carried out for a four vent configuration which showed an increase of 131% in the average in-cabin air velocity over the baseline model without any roof-vents.

Every class of commercial vehicle has an entirely different usage pattern based on customer application and needs. To perform accurate durability testing, these prototypes should run on real customer usage locations and loading conditions for the target life. However, this is time consuming and not practical, hence resulting in Proving Ground (PG) testing. It is also known that a standard PG durability cycle cannot be valid for every class of vehicle and every application. So a statistical approach was followed to develop an accelerated durability test cycle based on in-house PG test surfaces in order to match the real customer usage to the durability target life. This paper summarizes the methodology to develop Durability Validation test cycles for commercial vehicle based on the work carried out on a heavy duty tipper and an intermediate commercial vehicle.

Demand for a refined Heavy Commercial Vehicle (HCV) is increasing due to rapid Indian economic growth, while the operating conditions and road infrastructures are still in a transition state of development. The same vehicle model will be operated in a range of operating road conditions like mining sites, construction sites, and highways with varying payloads and speeds by customers that are spread across the country. This variety of road inputs, payloads and speeds has made ride tuning as one of the major challenging process in the development process. This paper describes the attempt to assess ride comfort of HCV with fully suspended cab using numerical based simulation tools and its correlation with physical test results. The best suspension combination was finalized based on vertical and pitch acceleration at Center of Gravity (CG) of the cab. The trend of vertical acceleration obtained from the virtual model was correlated with the same obtained from physical test.

In this work, durability of the bus structure is evaluated with a Virtual Test Model (VTM).Full vehicle Multi Body Dynamics (MBD) model of the bus is built, with inclusion of flexibility of the bus structure to capture structural modes. Component mode synthesis method is used for creation of flexible model for use in MBD. Load extraction is done by performing MBD analysis with measured wheel inputs. Modal Superposition Method (MSM) is employed in FE along with these extracted loads for calculation of modal transient dynamic stress response of the structure. e-N based fatigue life is estimated. The estimated fatigue life from the modal superposition method show good correlation with the physical test results done in 6-poster test rig.

Based on customer application and loading condition, each Commercial Vehicle model has an entirely different usage pattern. To perform accurate durability validation, each vehicle model prototype should run on actual customer usage locations and loading conditions for the durability target kilometers. But it is time consuming and not practical. So a statistical approach is followed to generate the accelerated durability test sequence and target on in-house Proving Ground tracks to match the real customer usage for the durability target kilometers. Again a single durability test sequence and target cannot be followed for all vehicle models due to the variability in customer usage. For that, specific durability test sequence and target need to be established for every class of commercial vehicle. This paper summarizes the methodology to develop Durability test sequence and target for commercial vehicle based on the work carried out on variants of medium and heavy duty trucks.

Automotive vehicles are subjected to a variety of loads caused by road undulations. The load history data measured from the roads are one of the vital input parameters for physical test as well as virtual durability simulation of vehicles. In general, the automotive vehicles are instrumented and subjected to a variety of driving conditions in diverse roads to obtain representative road load time histories. Acquired road load time history signals from various roads are exhaustive and repetitive in terms of both time length and data size. This results in more computation and virtual simulation processing. Hence it is imperative to reduce the input time signals without compromising on the representation of the actual operating conditions. Signal reduction of measured road load histories for virtual simulation assumes greater significance for durability prediction.

Durability analysis is essential for vehicle validation and is carried out with the inputs of different road conditions. The selection of roads for durability analysis is critical and should represent the actual working conditions for the selected vehicle. Generally, the road conditions are subject to change with respect to time. To overcome the above, road profile data is an essential parameter which helps to represent and categorize roads in terms of ISO (International Organization for Standardization) road class. The ISO road classes objectively classify the roads with respect to roughness. This classification holds good by categorizing the signals to the respective road classes rather than different test roads. The road profiles are measured using inertial profiler methodology along with vehicle acceleration and displacement responses, also analyzed and categorized with respect to ISO road class.

To capture market share in different regions of the world, the product must fit different road profiles and operating conditions. Designing a product which suits two different markets requires many factors to be considered like the topography, driving pattern and road load profiles. This project deals with once such situations and required a stringent validation protocol which shall encompass all possible driving scenarios. The fully built vehicle is to be exported to a different market and required powertrain change and subsequently required a new cradle design. Customer usage and road profile study was carried out in the new market to estimate the percent operation in each zone i.e. good road and bad road. CAE analysis carried out to capture stress hotspots and possible failure locations. Vehicle is taken to road to measure frame acceleration at different speeds i.e. 40 kmph to 100 kmph.

In the present scenario, delivering the right product at the right time is very crucial in automotive sector to grab the competitive advantage. In the development stage, validation process devours most of the product development time. This paper focuses on reducing the validation time for damper (shock absorber) variants which is a vital component in commercial vehicle suspension system. New test facility is designed for both performance test and endurance testing of six samples simultaneously. In addition, it provides force trend monitoring during the validation which increases the efficiency of test with an enhanced control system. This new facility is also designed to provide side loading capability for individual dampers in addition to the conventional axial loading. The key parameter during validation is control of damper seal temperature within the range of 70-90°C. A cooling circuit is designed to provide an efficient temperature control by re-circulating cold water.

Vehicular Emission testing is gaining importance over the past years in the wake of requirements for real driving emissions with implementation of RDE packages across Europe / USA and various developing countries. Extending the same concept for other countries poses slight challenges in terms of geographical and climatic conditions prevailing in the country, where the climatic conditions are differing from Europe / USA. It is a challenge to accept the same boundary conditions as in Europe, at the same time the challenge is to find a threshold number in a more scientific manner. This study concentrates on determination and recommendation of thresholds for ambient temperature and altitude. The basis for temperature threshold would be to determine the percentage of time the temperature exceeded beyond the threshold over year in the country. The basis for Altitude is considered based on the percentage of total length of roads beyond the threshold altitude limit.

The automotive industry is constantly looking for new alternate material and cost is one of the major driving factors for selecting the right material. ABT is a safety critical part and care has to be taken while selecting the appropriate material. Polyamide (PA12) [1] is the commonly available material which is currently used for ABT applications. Availability and material cost is always a major concern for commercial vehicle industries. This paper presents the development of ABT with an alternative material which has superior heat resistance. Thermoplastic Elastomer Ether Ester Block Copolymer (TEEE) [3] materials were tried in place Polyamide 12 for many good reasons. The newly employed material has better elastic memory and improved resistance to battery acid, paints and solvents. It doesn't require plasticizer for extrusion process because of which it has got excellent long term flexibility and superior kink resistance over a period of time.

With a push for urbanization across cities, there is an increased demand for mobility in public transportation especially buses which are provided through state transport undertakings. Hence, the expectations of this class of vehicles will be high in terms of quality and comfort to the passengers. The noise inside the passenger area of the bus becomes an important parameter, which sets apart a bus manufacturer from its competitors. The driveline of the bus is the system responsible for the transfer of power from engine to the wheels. The noise and vibration problems associated with it are detected only in the late stages of the design chain, when all its elements are tested together over a wide range of conditions. Since, calibration of engine and the selection of transmission is freezed in early stages, satisfying power and torque requirements, the only viable option left to address the problem is by optimizing the clutch parameters.

In the modern automotive sector, durability and reliability are the most common terms. Customers are expecting a highly reliable product but at low cost. Any product that fails within its useful life leads to customer dissatisfaction and affects the reputation of the OEM. To eradicate this, all automotive components undergo stringent validation protocol, either in proving ground or in lab. This paper details on developing an accelerated lab test methodology for steering gearbox bracket using fatigue damage and reliability correlation by simulating field failure. Initially, potential failure causes for steering gearbox bracket were analyzed. Road load data was then acquired at proving ground and customer site to evaluate the cumulative fatigue damage on the steering gearbox bracket. To simulate the field failure, lab test facility was developed, reproducing similar boundary conditions as in vehicle.

Sustainable development is the ultimate focus for all the upcoming inventions and innovations in the modern world. Automotive manufacturers contribute their research in terms of producing eco-friendly vehicles since it is proven that internal combustion engine–powered vehicles directly affect the air quality with their polluting exhaust gas. The rapid emergence of zero tailpipe emission vehicles such as electric and fuel cell electric vehicles (FCEVs) obtained the attention of major automotive giants worldwide. owing to their green mobility, battery-operated electric vehicles have already hit the road despite the challenges of recharging time, availability of recharging stations, range-to-weight ratio, and battery life and its recycling process. Drastic upscaling research and development of hydrogen FCEVs paves the way to reach the goal of sustainable transportation with its air cleaning effect, long range, zero tailpipe emission, and quick refueling time.