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In the past decades, many impressive progress has been made in the rig development for the gear validation. But, the challenges are to test the entire gear box for the improvement in the single gear alone to ascertain material quality or process improvement, that too with the higher torque range gear boxes, which requires huge investment and power consumption due to high capacity test rig / dynamometer. This paper deals with an experimental validation of the dynamic model for a gear pair test system, representative of a closed loop power recirculating type test rig. Being a closed loop, this system has its own uniqueness, that, it uses the low capacity prime mover, which considers the initial starting loop torque only, to cater the high power requirement in an efficient manner. The key intend of the development of this rig is to reduce the testing from system level to sub component level with low cost operation and more competence for the gears of high torque application.

Bogie-type suspensions for trucks are comprised of two axles and a central spring pack on each side of the truck chassis. Bogie suspensions have a good load distribution between the axles and are used for severe applications in trucks, in off-road conditions thereby subjecting them to extreme stain and load. In today’s competitive market scenario, it of utmost importance to minimize down time in commercial vehicles as it directly corresponds to loss in business which leads to customer dissatisfaction. It is therefore essential to optimize and select the right material for each component in the bogie suspension system. This paper deals with the material selection and testing of one such component - Bogie Wear Pad. The bogie wear pad undergoes sliding friction throughout its lifetime during loading and unloading of bogie suspension. Three different materials are selected and their wear is measured under the same conditions of loading.

In today’s commercial vehicle scenario, designing and developing a component which will never fail throughout its lifespan is next to impossible. For a long time especially in the field of automotive, any crack initiation shall deem the component as failed and the design requires further modification. This paper deals with studying the failure of one such component and understanding the effect the crack has on the overall life of the component i.e. understanding the remnant life of the component. The component under study was gear shift lever bracket and is mounted on the engine exhaust manifold. It experiences two types of loads: inertial load due to the engine vibration and gear shift load. Frequent failures were observed in the field and in order to simulate it at lab, an accelerated test approach was adopted. The engine operating speed was used to identify the possible excitation frequency which the component might experience.

The objective of this paper is to provide a reliable and robust mechanics based analytical approach for the accurate prediction of residual stresses in cold formed steel members. The forming residual stresses and associated equivalent plastic strains in cold formed corner sections are predicted with the assumption of elastic-perfectly plastic material model. The predicted analytical solution results are then compared with the existing analytical solution results. This work demonstrates that the exact estimation of forming residual stresses and equivalent plastic strains are possible with the inclusion of shift in neutral axis resulting from unequal thresholds of plasticity levels at the top and bottom surfaces of small radius corner sections. The predicted forming residual stresses and the associated equivalent plastic strains together define the initial conditions of corner sections for further non-linear structural behavior analysis of cold formed structures.

A full-bodied validation of automotive system emphasis on a comprehensive coverage of failure modes of component on one hand and evaluation with full system for the intended function of single component on the other has for long been cumbersome to most commercial vehicle manufacturers. This paper focuses on optimizing the test method in rig testing to relieve the complexity in the structural validation as whole system level. The methodology proposed by authors focuses on accelerating the vibration testing of component by compressing the validation timelines by using CSCPV (Combined Systematic Calculated and Pre Validation) method. This method selects the components of the system for validation by VFTM (Vital Few and Trivial Many) approach from existing testing database failure data and selects the worst predominant failure cases. This CSCPV method uses systematically calculated representing mass from analysis to validate the intended component alone instead of entire system.

New legislation’s, competition from global players and change in customer perception related to comfort parameters are key factors demanding manufactures to design and manufacture vehicles with very low saloon noise levels. The main causes for higher noise levels at passenger saloon compartment can be attributed to source noises (Powertrain, Driveline, Intake and Exhaust etc.), acoustic isolation and structural sensitivity of the body. Out of all above parameters, powertrain noise and acoustic isolation are two critical parameters effecting interior noise performance. This paper is an attempt to explain acoustic source contribution analysis through transfer function measurement in a passenger vehicle. Acoustic transfer function between engine bay and passenger ear level was measured using reciprocity technique (reciprocal method) with reference source placed at various locations inside the vehicle.

Bio-fuels potentially represent a more environmentally friendly alternative to fossil fuels as they produce fewer greenhouse gas emissions when burned. Ethanol is one such bio-fuel alternative to the conventional fossil fuels. Towards the initiative of sustainable transportation using alternative fuels, it is attempted to develop an ethanol powered engine for commercial vehicles and this paper attempts to explain the 1D thermodynamic simulation carried out for predicting the engine performance and combustion characteristics, as a part of the engine development program. Engine simulation is becoming an increasingly important engineering tool for reducing the development cost and time and also helps in carrying out various DOE iterations which are rather difficult to be conducted experimentally in any internal combustion engine development program. AVL Boost software is used for modeling and simulation.

The mechanical and wear behaviour of an alloyed gray cast iron with ausferrite microstructure directly obtained on solidification has been compared with austempered alloyed gray iron. As-cast ausferritic gray iron shows finer ausferrite and graphite flake morphology compared to austempered alloy. The volume of retained austenite is about 30% higher in as-cast ausferritic iron due to higher amount of alloying additions. The mechanical and wear properties of as-cast ausferritic iron are almost similar to austempered alloy.

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.

All automotive components undergo stringent testing protocol during the design validation phase. Nevertheless, there are certain components in the field which are seldom captured during design validation. One of these components is the battery isolator switch. This project aims at optimizing a validation methodology for this component based on field usage and conditions. The isolator switch is the main control switch which connects and disconnects the electrical loads from the battery. This switch is used in the electrical circuit of the vehicle to prevent unwanted draining of battery when it is not needed and when the vehicle is in switched off. An electrical version of this switch uses electromagnetic coils to short the contacts. The failure mode being investigated is a high current load causing the input and output terminal to be welded.

Commercial vehicle payload depends on the client for which the vehicle fleet owner is operating. Load carriers like flatbed trailer offer the flexibility to be loaded with a large number of light payloads or a few numbers of massive payloads. Such load carriers have to be evaluated for various possibilities of loading patterns that could happen in the market. The objective of this work is to evaluate flatbed trailer for its structural strength for different customer application cases, using computer simulation. Structural load cases due to payloads like containers, steel coils and cement bags are arrived at. Static structural analysis using MSC Nastran is performed to evaluate for the worst customer loading pattern from structural stress point of view. This paper also describes a simplified method for simulating the effect of trailer suspension, tractor suspension and the fifth-wheel coupling in the analysis whose detailed modeling is not possible at the concept level.

CABIN design is continuously undergoing a huge change for reasons of customer comfort on for meeting regulatory requirement. Consequently the strategic design process will not only consider need for high strength structures but a pragmatic research based approach utilizing the latest technology. Though cab structure is built by a sheet metal blank as per the required dimensions, some locations encounter great amounts of stress and must be designed to withstand the same in a durable way. A possible simpler practice would be to add reinforcements in the high stress area or use high strength material for the entire part. However in this approach weight and cost of the component will be increased. As the weight of the Cabin, vehicle increases this will impact fuel efficiency. Attempts have been taken like using composite materials.

The cost incurred to make design modifications to solve NVH problems increases with maturity of design in the development process. Hence NVH issues should be addressed in the initial phase to avoid any significant changes in structure and subsequent changes in overall performance of the vehicle. Hybrid methodology with application of advanced testing and Computer Aided Engineering (CAE) tools to achieve full vehicle NVH attribute targets is nowadays a must for this reason. This paper represents a case study on low frequency NVH performance evaluation and refinement for heavy commercial vehicle truck using Hybrid Test-CAE methodology. To achieve better NVH performance, it is important to set competitive overall vehicle level NVH targets and cascade it down to system and sub-system targets. Test-CAE correlation has been carried out to validate Finite element (FE) modeling procedure and methodology.

Ventilation is a crucial factor affecting passenger comfort in any vehicle. In a non-air-conditioned bus, ventilation caters to the dual requirement of fresh breathing air as well as providing a cooling sensation by enhanced evaporation of sweat. The higher the velocity of air around the passengers, the greater the cooling effect experienced by them. The ventilation mechanism of a non-air-conditioned bus is primarily the air flow through the windows due to relative motion between the bus and the air around it. This paper describes studies carried out to identify the right combination of open windows which would provide optimum air flow at the passenger head level plane in a bus. A bus model with 12 windows, 6 on each side is used for the study and air velocity at certain points in the head level plane, arising out of different combination of window openings is evaluated using CFD.

In heavy commercial vehicle segment in India, driver comfort and feel was largely ignored. Fierce competition in the recent years and buyer’s market trend is compelling the designers of heavy truck to focus more on the finer aspects of attribute refinements. Steering is one driver-Vehicle interface which the driver is engaged throughout. Comfort and feel in steering wheel is defined by parameters like steering effort, manoeuvrability, on-center feel & response, cornering feel & response, Torque dead band, return-ability etc. and is influenced by a long list of components and systems in the truck. This study focuses on the influences of jacking torque and steering system friction on the on-center driving performance. Experiments to measure the Jacking torque and steering system friction were conducted in the lab and subjective and objective assessments of on-center driving performance were later conducted at test track in two similar 12 Ton truck to correlate their effects.

Automotive component light weighing is one of the major goals for original equipment manufacturers (OEM's) globally. Significant advances are being made in developing light-weight high performance components. In order to achieve weight savings in vehicles, the OEM's and component suppliers are increasingly using ultra-high-strength steel, aluminum, magnesium, plastics and composites. One way is to develop a light weight high performance component through multi material concept. In this present study, a bimetal brake drum of inner ring cast iron and outer shell of aluminum has been made in two different design configurations. In two different designs, 40 and 26% weight saving has been achieved as compared to conventional gray cast iron brake drum. The component level performance has been evaluated by dynamometer test. The heat dissipation and wear behavior has been analyzed. In both designs, the wear performance of the bimetal brake drum was similar to the gray cast iron material.

In this paper, experimental evaluation was carried out on a 6.0 L heavy duty CNG engine which has been optimized for 18 percent hydrogen blended CNG (HCNG). Optimization test results shows that use of HCNG results in reduced CO, THC & CH4 emissions by 39, 25 & 25 percent respectively and increase in NOx by 32 percent vis-a-vis CNG. After optimization the engine was subjected to endurance test of 600 hours as per 15 mode engine simulated city driving cycle with HCNG. The performance & emission characteristics of the engine were analyzed after completion of every 100 hours as per European Transient Cycle (ETC). Test results indicate that there were no significant changes observed in engine power output over the complete endurance test of 600 hrs with HCNG. Specific fuel consumption (SFC) measurements were consistent at all the 15 modes of engine simulated city driving cycle.

Steering gear box function is one of the important requirements in heavy vehicles in order to reduce driver fatigue. Improper functioning of steering gear box not only increases the driver fatigue, also concerns the safety of the vehicle. In this present investigation, the engine oil mixing up with steering oil has been identified and steering gear box failure has been observed in the customer vehicle. The root cause of failure has been analyzed. Based on the investigations, in particular design of steering pump has been failed at customer end. The same design of steering pump were segregated and analyzed. Initial pressure mapping study has been conducted. The pressure mapping results revealed that the cavity pressure obstructs the flow of suction pressure. It indicates that obstacle at suction port due to the existence of internal leakage that causes back pressure in the internal cavity of steering pump which sucks engine oil.

The commercial vehicle industry is evolving faster with the rise in multifarious aspects deciding a company's progress. In the current scenario, vehicle performance and its reliability in the areas of payload, fuel economy, etc. play vital roles in determining its sustenance in the industry, in addition to reducing driver fatigue and improving comfort levels. Test quality and time is the key to assure and affirm, smooth and quick launch of the product into the market. This paper details on the design of Multi-Axis road data simulator which entails realistic loads onto the components for capturing meaningful information on behavior of the product and recreate the field failure modes. The design was conceptualized keeping in mind both cost (for initial installation and running cost) and time for testing without loss in the convergence factor.

The emerging trends in commercial vehicle technology have increased the necessity for critical attribute engineering refinements. Drivability is emerging as one of the most significant attributes in the automotive sector. The degree of smoothness in a vehicle's response to the driver's input is termed as drivability. This attribute has to be rigorously refined in order to achieve brand specific vehicle characteristics, which will ensure a thorough product differentiation. In order to calibrate for a positive drivability feel, a methodology for evaluation of drivability is a prerequisite. The scope of this paper is aimed at describing the methodology for subjective and objective evaluation of drivability attributes in commercial vehicles. Drivability is a highly subjectively perceived attribute, therefore a subjective assessment technique to assess drivability attributes and sub-attributes are essential.