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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.

One of the important methods by which vibrations of a body are reduced is by the use of vibration absorbers or tuned absorbers. This technique involves attaching a spring mass system, called absorber system, to the vibrating body (also called primary body). This paper is a case study dealing with a primary system, here a driver seat, to attenuate its response to disturbance. It has high damped natural frequency compared to the base excitation frequency, which was collected from test data. The paper discusses the variations in absorber and primary system damping ratio, mass ratio variation and usage of variable stiffness. Detailed analysis showed instability in the tuned system due to the large gap between the primary body's damped natural frequency, and the target base excitation frequency. In order to address varying target excitation frequency, an adaptive tuned absorber is suggested.

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.

Driver safety is one of the key considerations in truck design and development. Virtual simulation offers opportunities to reduce development time and the number of physical prototypes consumed for design verification and validation for safety parameters. Thus, the application of virtual simulations of crash has become an integral part of the vehicle development process. The continuously emerging scenarios involving challenging test requirements can only be tested by means of virtual simulation techniques. This paper presents simulations that are performed to verify various safety aspects to ensure crashworthiness of the truck cabin. The cabin structure was evaluated for various national/international safety regulations. The FE model and simulation methodology was validated through physical testing and correlated for frontal impact test and roof strength test as per AIS 029/ECE R29. Analysis performed to ensure compliance to upcoming regulation ECE R29 Revision 03 is also discussed.

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.

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.

The automotive industry is heading towards introduction of newer and newer technology aimed at providing better comforts and value to the end user. The public/ private transport vehicles in urban/rural areas with FE has wide level of acceptance in South East Asian countries. The acceptance of FE buses is mainly because of the ram air cooling of the engine, lesser maintenance, higher fuel efficiency etc whereas rear engine buses with entry plus one step are deprived of these benefits. Hence, we have designed and developed a new Front Engine Semi -Low Floor bus having floor at E+1 step. The primary design challenge was to meet the uniform floor throughout the length of the vehicle. This uniqueness will help in easy ingress and egress of the passengers which helps in reducing the turn around rime of the vehicle. Other challenges includes, meeting the customer requirements in terms of application, load and duty cycle for this new design.

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.

Fuel economy is an important customer requirement which determines the position of earth-movers such as backhoe loaders in the market. Earth-movers are heavy duty machines that are used for construction works. Currently fuel consumption in earth-movers is quantified as fuel consumed per unit time (Liters per hour). Similarly, conventional measure of productivity of the earth-movers is in terms of volume of soil trenched per hour. Measurements using the above scales showed wide variations in measured fuel consumption and productivity, For the same equipment between measurements Two equipment of same make at different trench locations and Against the competitor equipment This inconsistency and lack of a proper measuring system made logical decision making extremely difficult. This paper describes the step by step procedures involved in deriving the methodology for robust fuel consumption measurement of earth-mover vehicles.

The present work describes an approach to predict the vehicle fuel economy by simulating its engine drive cycle on a transient engine dynamometer in an engine testbed. The driving cycles investigated in the current study were generated from the typical experimental data measured on different vehicles ranging from Intermediate Commercial Vehicle (ICV) to Heavy-duty Commercial Vehicle (HCV) in real-world traffic conditions include various cities, highways and village roads in India. Reliability and robustness of the method was studied on various engines with cubic capacity from 3.8 liters to 8 liters using different drive cycles, and the results were discussed. Later, using same measured drive cycles, vehicle fuel economy was predicted by a vehicle simulation tool (AVL CRUISE) and results were compared with experimental data. In addition, engine coolant temperature effect on fuel economy was investigated.

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.

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).