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The paper describe investigations on the vibration characteristics of a gasoline engine due to piston slap and a diesel engine due to combustion. Engine parameters and vibration data were recorded and time series signals were obtained. The effect of speed, load and other engine parameters on vibration is investigated. Vibration due to piston slap is analysed with reference to major-minor thrust relationship, cylinder to cylinder variation, piston-slap force diagram and vibration-frequency curves. The experimental results suggest that all reciprocating engines would exhibit a complex vibration pattern due to piston slap at harmonic series of discrete frequencies, and the reason for this is analysed. The vibration transmitted by engine structure in response to the in-cylinder pressure development is termed here as ‘Vibration due to Combustion’ and is assessed from the spectrum of the Combustion Pressure curves and their derivatives in terms of time.

Environmental pollution is of great concern; hence the emission norms for the diesel engines are made more stringent. The purpose of this work is to develop a process to optimize the FIS parameters and select a most suitable FIS by simulation to meet the target emissions. During the combustion optimization exercise of diesel engine, different hardware combinations like injector, HPP etc are matched through testing to achieve the required performance and emissions. The process requires the real testing of the engine on engine dynamometer with various hardware combinations, which is expensive and time consuming. A simulation model of diesel FIS is constructed using ‘AVL Hydsim’. The model is validated by comparing the predicted and the experimental results. The validated model is used for further work. Critical parameters were listed based on the sensitivity analysis on the base model.

Suspension development is one of the key steps in a complete vehicle development program. Computer simulation and analysis tools such as Multi Body Dynamics (MBD) simulation are used to refine initial concept and suspension parameters. Later on when a physical prototype is available the suspension system can be experimentally optimized at vehicle level. In this paper a new methodology is proposed which integrates virtual and experimental tools so that design, development and validation of the suspension system is carried out in the early phase of the vehicle development cycle with actual suspension components and without the need of a vehicle prototype. With this new approach, the design of any critical suspension components such as dampers can be optimized at the vehicle level. The new approach consists of combining the actual physical components on loading rig in closed loop with vehicle dynamic model running in real time.

Seat system resonant frequencies play an important role in seat design and ride dynamics. So NVH performance of the seats should be assessed from the viewpoint of tactile, acoustic and visual sense. Tactile response is the response of sub-systems, which is induced when the human body contacts steering wheel, footrest or seats. Acoustic response is the behavior of the seat system at the cavity resonance frequencies and visual sense is what we perceive under actual operating conditions. The objective of the present work is to conduct and correlate experimental modal test with FE modal test to identify tactile vibrations. Then the identified main seat modes will be used to set the mode map (seat target) at the stage of full vehicle level. This work will present a practical approach in understanding varied methods and techniques for determining resonant characteristics and for subsequent refinement of FE model.

New process development of forging component require lot of process knowledge and experience. Even lots of trial-and-error methods need to be used to arrive at optimum process and initial billet dimensions. But with help of reliable computer simulation tools, now it is possible to optimize the complete process and billet dimensions without a single forging trial. This saves lot of time, energy and money. Additionally, simulation gives much more insight about the process and possible forging defects. In this paper, a complete forging process was needed to be designed for a complex component. With the help of computer simulation, the complete conventional forging process and modified forging process were simulated and optimized. Forging defects were removed during optimization of the process. Also billet weight optimization was carried out. Deciding the pre-forming shape of the billet was the main challenge.

In today’s automotive industry sound package material design and optimization is important considering the need for weight reduction and achieving targeted sound absorption and sound transmission loss values. As per traditional approach vehicle level noise reduction targets are defined considering flat samples, but in actual vehicle condition molded trimmed parts are used. This paper discusses about the systematic methodology developed for molded sample characterization in terms of BIOT’s properties. Effects of different parameters like area wise thickness variation, density variation on BIOT properties is studied. Comparison of BIOT’s properties of flat and molded dash sample is done to study the effect of molded structure. Using these BIOT’s properties prediction of sound absorption and sound transmission loss results carried out using FTMM approach for flat sample and SEA approach for molded sample.

Any metal component undergoes various treatments to get desired shape and desired properties. Some of the important properties are strength, hardness, % elongation etc. which comes under mechanical properties. These properties can be easily achieved through heat-treatment process. Typical example of heat-treatment processes are hardening and tempering in case of steel and aging process in case of aluminium alloys. Some of the new emerging materials viz. micro alloy steel does not require any hardening and tempering if cooling rate is maintained. Heat-treatment cycle depends on material grade and its alloying elements. A heat-treatment cycle for any grade is generally fixed based on conventional methods but they are not optimized. The need of hour is to optimize the heat-treatment cycle to improve productivity and energy consumption. Dilatometer is used to optimize heat-treatment cycle on sample level whereas simulation tools can be used for component level.

The objective of this study is to develop, demonstrate and validate the methodology of external aerodynamic analysis of a State Road Transport bus for prediction of drag coefficient and its impact on fuel consumption with experimental validation. It has been verified that vehicle consumes around 40% of the available engine power to overcome the air drag. This gives us a huge scope to study the effect of aerodynamic drag. Baseline model of State Road Transport Bus was evaluated for estimating fuel consumption using Computational Fluid dynamics (CFD) methodology. The CFD results were validated with the experimental data with less than 10% deviation. Bus design was optimized with an objective of reducing the fuel consumption with parameters like angle of windshield, rounding and tapering corners and rear draft angle. Optimized bus design is also ensured to meet functional specifications as per AIS052.

Diesel engine generators are commonly used as a power source for various industrial and residential applications. While designing diesel generator (DG) enclosures requirements of noise control, ventilation and physical protection needs to be addressed. Indian legislation requirement demands DG enclosure insertion loss (IL) to be minimum 25 dB. However for certain critical applications like hospitals, residential apartments customer demands quiet DG sets than the statutory limits. IL targets for such application ranges between 35-40 dB. The objective of this paper is to develop methodology to design ‘Super Silent’ enclosure with IL of 35 dB by Statistical Energy Analysis (SEA) approach for small capacity DG set. Major challenge was to achieve IL of 35 dB with single enclosure and making use of SEA technique for small size enclosure wherein modal densities is very less. Major airborne noise sources like engine, radiator fan and exhaust were modelled by capturing noise source test data.