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The gearbox is a crucial aggregate in a diesel truck. Gearboxes must work efficiently to get the job done properly and lubrication is vital to this efficiency. Lubricating oil is like the circulation system of a gearbox. If the oil levels fall too low, the gearbox will likely fail. Gearbox failure can lead to expensive repairs that could be prevented. Besides added costs due to replacement or repair, costs associated with a loss of production could be significant. These issues are why; it is important to understand the consequences of having low lubricant levels. Similarly, higher oil level creates higher churning losses, heating of the Gear oil and oxidation, reduction in efficiency and increased oil leaks. Understanding the functions of gearbox lubricating oil can help you choose the right quantity of prevent gearbox failures.

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.

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.

A case study was conducted on the design, optimization and material replacement for an automobile suspension link. The link is part of a four bar mechanism. The mechanism was developed in Adams/Car® and multibody simulation was carried out on it. The joint forces arrived from the simulation were exported for finite element analysis of the components in OptiStruct®. Finally, topology and shape optimization was conducted to reduce the weight of the original component. A feasibility study was also carried out to replace the fabricated steel link with a heat treated cast iron link. Heat treated cast iron being lighter than steel, ensures reduction in weight without compromising on strength. The experiment resulted in a feasible optimized shape which was 32% lighter than the current shape of the link being used in the vehicle, while keeping the stresses and displacements within limits.

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.

Driver's ride comfort is an important characteristic in heavy commercial vehicle cab design. Optimizing the ride behavior for different cab variants and vehicle applications is a challenge for cab design and development engineers. Suspension parameter tuning with physical test is time consuming and costly. Therefore, a lumped parameter quarter car model of suspended cab is developed in MATLAB® tool SimScape which includes cab mass, springs and dampers for predicting ride behavior as per ISO 2631. The study is done for a 25 t rigid truck. The input to the system is displacement at axles and the output is acceleration measured at cab and chassis level. This output is correlated with test data obtained from physical measurements using Power Spectral Density (PSD) curves, bode plots and level cross count. This proved that simple lumped parameter models which use very few input parameters can be effectively employed in analysis of cab ride in initial design phases.

The primary factors influencing vehicle's dynamic behavior are the vehicle hard point definition, driver behavior and road inputs. The more the latter two are random and incorrigible in nature, the former one is quantifiable and can be controlled from designer's standpoint. In this paper, we have made an attempt to set targets to the vehicle hard point definition and thereby to optimize the vehicle for better ride behavior. This approach hence helped to converge to vehicle specifications set fundamentally designed to respond to random operating conditions and driving behavior intelligently. The work also involves study of various methodologies to predict roll, pitch, bounce and dive behaviors on a typical commercial passenger vehicle and is concluded by a sensitivity analysis to understand significance of these hard points on vehicle's real time behavior.