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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.

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.

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.

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.

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 Heavy Duty live rear axles in commercial vehicle helps to transmit the drive to the rear wheels and also carries vehicle load. The rear axle along with wheel assembly consists of axle casing, differential unit, half shafts, wheel hub, brake drum, brake chamber and wheels. It is one of the major safety critical element in any commercial vehicle. Based on the suspension type, rear axle housing also carries V rod & radius rod mountings & Spring Seat /Wear pad / Rubber Bolster (in case of bogie suspension). This paper abbreviates the contribution of bogie suspension seating configurations & V-rod Forces on life of heavy duty bogie rear axle casing. In-service DRT hot spot observations were reported on heavy duty rear axle on few models with bogie suspension. In order to find the root cause, devising a proper testing and analysis method is of prime importance. An extensive effort was made to device test methodology based on customer application and field visits.

Lifting axles are auxiliary axles that provide increased load carrying capacity in heavy commercial vehicles. Lift axle gives better fuel efficiency as well as it reduces the operational costs by means of increasing the loading carrying capacity. These axles are raised when the vehicle is in unloaded condition, thus increasing the traction on remaining wheels and reducing the tire wear which in turn lower down the maintenance cost of the vehicle. Lifting height and force requires to lift the whole mechanism and are two main considerable factors to design the lifting axle mechanism. Although in India currently, the use of lift mechanism of single tire with continuous axle is more common. But in the case of pusher axle, continuous axle is unable to lift more after certain height because of the draft angle of the propeller shaft, and single tire axle which has less load carrying capacity up to 6T (Tons).