Search Results

In the commercial vehicle business, vehicle availability is a pivotal factor for the profitability of the customer. Nonetheless, the intricate nature of the technologies embedded in modern day engines and exhaust after-treatment systems coupled with the variability of the duty cycles of end applications of the vehicles imposes added challenges on the vehicle's sustained performance and reliability. In this context, the ability to predict potential failures through tools like telematics and real-time data analytics presents a significant opportunity for original equipment manufacturers (OEMs) to deliver distinctive value to their customers.

The conventional internal combustion engines continue to dominate many fields like transportation, agriculture and power generation. Moreover, apprehension over oil price restriction has created an unprecedented demand for fuel economy. Diesel engine is mostly preferred for its higher thermal efficiency, high-torque and outstanding longevity. In recent days with flooded technologies, Uniqueness and the Differentiation of Product play vital role for a successful business in Auto Industry. The present invention is related to the Challenges of Design & Development of Conventional Diesel Engine to meet the stringent emission & performance requirements (BS-IV) of Internal Combustion engines, and more particularly to achieve the targets with conventional Fuel Injection Systems (Non-electronic Fuel Injectors, In-Line Fuel Injection Pump-Governed Electronically) with required sub-systems on IC engine.

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.

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 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.

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 competitive vehicle market, the product must be designed and validated in shorter time span without compromising the quality. The durability of the vehicle is tested either by on road trials undertaken at the actual customer supplication sites for large time period or in the accelerated rough surfaces called “Proving ground” to validate in shorter time span. Accelerated proving ground durability testing plays a vital role in enabling shorter product development cycles by simulating the road load influences alone from the actual field conditions. It is imperative to simulate the test vehicle at proving ground (PG) testing such that it replicates the same damage that occurs in the field due to road loads. PG validation requires a specific durability test sequence for every segment of commercial vehicles due to different customer usage applications and terrain conditions. This diversity in applications and terrains induce structural damage at different range of frequencies.

Powertrain is the major source of noise and vibration in commercial vehicles and has significant contribution on both interior and exterior noise levels. It is vital to reduce the radiated noise from powertrain to meet customer expectations of vehicle comfort and to abide by the legislative noise requirements. Sound intensity mapping technique can identify the critical components of noise radiation from the powertrain. Sound intensity mapping has revealed that oil sump as one of the major contributors for radiated noise from powertrain. Accounting the effect of dynamic coupling of oil on the sump is crucial in predicting its noise radiation performance. Through numerical methods, some amount of work done in predicting the dynamic characteristics of structures filled with fluid. This paper discusses on the capability of numerical approach in predicting the oil sump modal characteristics with fluid-structure interaction and consequent verification with experimental modal test results.

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.

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.

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.

Spring seat plays major role in bogie suspension; which is guiding and controlling the leaf spring for better suspension and also to withstand the compressive load from leafs. Currently used spring seats are failing frequently in medium and heavy duty vehicles, which lead to customer concerns by higher idle time and part replacement cost. Thickness of the spring seat can't be increased by large extent due to packaging constraints in the vehicle. Stress levels identified by FEA method are found higher than the current material capacity. With these constraints, the spring seat has been re-designed with improved strength and ductility of material by modern technology - Austempered Ductile Iron (ADI). The parts have been developed and assembled in various tipper applications and performance was studied. The developed spring seat shows five times superior durability compare to existing design.

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.

With increasing concern on energy security and energy efficiency, automobile industry has been conducting many research on technologies aimed at reducing weight and reducing fuel consumption thereby reducing carbon footprint of the vehicle without compromising safety, efficiency and operational ability. Alternative fuel vehicles such as Compressed Natural Gas (CNG), Liquefied Petroleum Gas (LPG), Hydrogen, Hydrogen-CNG (HCNG) blends and Liquefied Natural Gas (LNG) vehicles are some of the best solutions to minimize the dependence on fossil fuels which are depleting fast. Gas cylinders are the heavier portion of alternative fuel systems which adds more weight to vehicle unladen weight. In search of innovative materials for gas cylinders, composite materials have been the front runner in reducing weight of the vehicle, thereby reducing fuel consumption significantly.

Evaluation of vehicle structural durability is one of the key requirements in design and development of today's automobiles. Computer simulations are used to estimate vehicle durability to save the cost and time required for building and testing the prototype vehicles. The objective of this work was to find the service life of automotive structures like passenger commercial vehicle (bus) and truck's cabin by calculating cumulative fatigue life for operation under actual road conditions. Stresses in the bus and cabin are derived by means of performing finite element analysis using inertia relief method. Multi body dynamics simulation software ADAMS was used to obtain the load history at the bus and cabin mount locations - using measured load data as input. Strain based fatigue life analysis was carried out in MSC-Fatigue using static stresses from Nastran and extracted force histories from ADAMS. The estimated fatigue life was compared with the physical test results.

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 recent years NVH has gained a lot of importance in the commercial vehicle industry as it contributes significantly towards user comfort and also towards the quality perception associated with a vehicle. The in-cabin noise of vehicles is critical towards the comfort and usability for the end user and the sound package installed on the vehicle plays a vital role in determining the levels associated with this attribute, especially the high frequency content. The paper discusses a methodology for optimizing the sound package for performance, cost and mass, for a truck. The approach uses a Statistical Energy Analysis (SEA) based optimization. A virtual SEA model is developed, which is correlated with actual test data. After establishing the correlation, an optimization study is carried out to identify the effectiveness of different materials and material combinations towards in-cabin noise.