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Three on the tree, four on the floor. The gear change mechanism is a component that is too often taken for granted but it is one of the more important features of the vehicle. It must be quick and smooth in action, efficient and totally reliable. Modern driving conditions demand that the driver makes frequent gear changes and a mechanism that is temperamental or inaccurate can be both frustrating and dangerous as well as physically tiring. The gear changing mechanism starts, quite obviously, with the gear lever. Most stem from the fact that a gear lever must move in two planes, forward and back and then from side to side to move across the gear "gate". A good many drivers think of gear changing as one simple action. This is more a tribute to the design of gear changing mechanisms than a reality. There are multiple gear selector mechanisms that are available for use in commercial vehicle industry.

Manual Gear shifting mechanism is a customer touch point in vehicle driving conditions and it is a frequently used functional part of the vehicle. Inherent challenges exist to develop a gear shifting system that achieves better comfort shifting gears in manual transmissions, i.e. gear shift levers should be comfortable, efficient and reliable. There are several traditional concepts available for designing a mechanical interface for gear shift system like cable GSL (Gear Shift Linkages), mechanical GSL, engine mounted SRGSL (single rod gear shift linkages), directly transmission mounted GSL. All are having pros and cons over another. A unique attempt is made to provide an efficient single rod type gear actuation system for commercial vehicle where one end is directly mounted on the cowl floor of the bus/Truck and another end is connected to transmission lever.

The existing head cover is having external oil and blow by separation unit, which is not only costlier but also complex and leads to increase in overall height of engine which was difficult to integrate in new variants of vehicles. A new head cover has been designed with internal baffle type oil and blow by separation system to ensure efficient separation and proper packaging of the system in new variants. The new system has been finalized after 26 DOE’s of different wire mesh sizes and different baffle plate size and positions. The final system has two bowl shaped separation unit with wire mesh, two cup type oil separation passages and one baffle plate for separating blow by. The system works on condensation and gravity method. The blow by is guided through a well-defined passage integrated in aluminum cylinder head cover itself. The passage angle is maintained to ensure minimum oil flow with blow by.

The main driving force behind recent innovations in automotive sector is the need to decrease the dependability on fossil fuels and move towards alternative sources for energy. While there is still substantial scope for improvement in conventional diesel and petrol engine based powertrains, the inherent dependency on limited and rapidly depleting carbon based fuels make their long term usage impractical highlighting the need for alternative non-conventional powertrain setups. In the recent past, electric powertrains have come out as favorable alternative as they are extremely flexible in adopting to scenarios where energy for use might be drawn from multiple sources such as solar power, hydroelectric, nuclear reaction, etc. The advantages can further be magnified by adopting the electric power based powertrains in mass transportation application such as bus application.

The planetary gear system is a critical component in speed reduction of gear system. It consists of a ring gear, set of planetary gears, a sun gear and a carrier. It is mainly used in high speed reduction transmission. More speed variation can be achieved using this system with same number of gears. This speed reduction is based on the number of teeth in each gear. The size of new system is compact. A theoretical calculation is performed at concept level to get the desired reduction of speed. Then the planetary gear system is simulated using ANSYS software for new development transmission system. The final validation is done with the testing of physical parts. This concept is implemented in 9speed transmission system. Similar concept is in development for the hub reduction with planetary gears. The maximum 3.67 reduction is achieved with planetary system. The stresses in each pin is calculated using FEA.

Proper sealing of an engine is very important parameter in an engine design. Even small amount of gas leakage from the engine can affect the overall performance of the engine during operation. There are two important factors in enhancing the efficiency of the sealing of the gasket are right tightening torque of bolts & gasket design. In this study, both the distribution of the contact pressure on the gasket, and the stresses of the cylinder head at different loading conditions, such as cold assembly, hot assembly, cold start, and hot firing, is simulated by commercial tool, based on the finite element method (FEM). The results shows that the efficiency of the sealing of the cylinder head gasket depends on the tightening torque of the hold-down bolts, without taking into consideration any thermal load resulting from the temperature distribution in the cylinder head.

In manual driven vehicle, gear change mechanism is a component that is too often taken granted but it is one of the most important feature of the vehicle. Customer touches, feels the entire vehicle through gear shift mechanism hence it must be quick and smooth in action, efficient and totally reliable. In cab over engine type truck configuration, the mechanical single rod is preferable and best efficient option for gear shift mechanism. In conventional single rod design, one end of gear shifting linkage is mounted on the engine through bracket and the lever comes inside from the cabin, beside the driver seat for changing the gears. Another end of this linkage is connected to vehicle transmission shift lever. In this conventional design, gear shift lever is having huge induced vibration, which is irritating and frustrating in nature. And during the cabin tilting at its axis, a cut out is required on cabin floor which allows cab tilting when GSL is mounted on engine.

A propeller shaft is a mechanical component of drive train that connects transmission to drive wheels/axle with the goal to transfer rotation and torque. It is used when the direct connection between transmission and drive axle is not possible due to large distance between their respective assigned design spaces. In commercial vehicles especially in heavy duty (GVW/GCW>15 tons) a single piece propeller shaft is seldom used due to its inherent disadvantages and therefore, most if not all, of the setups consists of multiple pieces of propeller shaft which are directly mounted on to frame cross members with the help of mounting brackets. As such the mounting bracket assembly undergoes various dynamic and static loading conditions and should be able to withstand these loads. This paper will focus on the FEA analysis of propeller shaft mounting assembly system. Furthermore, these results will be correlated with physical tests results collected from test rig and physical vehicle testing.

Advanced Non-linear topology optimization methods have been addressed as the most promising techniques for light weight and performance design of Powertrain structures. The theoretical achievements are obtained both mechanically and mathematically. Nowadays, the great challenge lies in solving more complicated engineering design problems with multidisciplinary objectives or complex structural systems. The purpose of this paper is to provide a forum to present new developments in structural Non-linear topology optimization. The advantage of the proposed method is that structural optimization on irregular design domains can be carried out easily. Furthermore, this method integrates the stress analysis and the boundary evolution within the framework of finite element methods. In this paper, mainly focused on the Commercial Vehicles Powertrain component i.e. Transmission Housing.