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Downsizing and Light weighting is the latest trend in the automotive industry to achieve more fuel efficient, compact and cost effective design of vehicles. Powertrain components compromise of more than 45% of the total vehicle weight. Automakers are putting significant efforts to reduce the weight of power train components. Integrated design of aluminum Engine Head and Intake manifold has been successfully implemented. Now currently we have identified the gear box housings for downsizing in light duty trucks i.e. Existing light duty trucks Cast Iron transmission. This design has been successfully modified with integrated clutch housing and transmission housing, using lightweight aluminum as the new material, using simulation tools. This lead to weight savings of up to 30% and cost savings of 20-25% as compared to existing cast iron designs. Using an integrated design reduces the assembly cost, makes the design more compact and gives better weight balance.

As the commercial vehicle engine heads towards the next generation of stringent emissions and fuel economy targets, all aspects of the internal combustion engine are subject to close scrutiny. Inherently, ICE’s are very inefficient, with efficiency varying between 18 ~ 40%. This efficiency is a function of friction losses, pumping losses and wasted heat. Currently, automotive OEM’s globally are hard at work trying to attack these issues with various solutions to achieve incremental gains. The leading trend is getting more power from less space, also known as downsizing. Due to the importance of downsizing, direct injection and other technologies, it is imperative to highlight another key area, where OEM’s are expanding their limits to gain those extra few kilometers per liter of fuel i.e. weight reduction. From an emissions perspective, it is estimated that every 50 kg of weight reduced from an average 1,500 kg vehicle cuts CO2 emissions by 4 ~ 5 grams.

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.

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.

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.

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.

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.

To compete with the current market trends there is always a need to arrive at a cost effective and light weight designs. For Commercial Vehicles, an attempt is made to replace existing Gear Shift Fork from FC Iron (Ferro Cast Iron) to ADC (Aluminum Die Casting) without compromising its strength & stiffness, considering/bearing all the worst road load cases and severe environmental conditions. ADC has good mechanical and thermal properties compared to FC Iron. Feasible design has been Optimized within the given design space with an extra supporting pad for load distribution. Optimization, Stiffness, Contact pattern has been done using OptiStruct, Nastran & Ansys for CAE evaluation. A 6-speed manual transmission is used as an example to illustrate the simulation and validation of the optimized design. Advanced linear topology optimization methods have been addressed as the most promising techniques for light weighting and performance design of Powertrain structures.

This paper presents theoretical calculation, analysis and simulation (validation and verification) of driveshaft torsion vibration. The vibration measurement validation verification has been carried out on vehicle (4x2) having four cylinder engine 85kw@2800 rpm and six speed manual transmission for getting correlation between values of theoretical calculations and CAE results. This analysis has been done in order to achieve vehicle good performance in terms of driving comfort as well as smooth functionality with zero vibration frequency at high speed. The propeller shaft series selection and refinement has been done using theoretical iteration with operating angle of prop shaft which exits in between the universal joint planes. A frequency of vibration analysis has evaluated at different propeller shaft layout and duty cycle. The vibration performance predictions for vehicles with these design is rigorously done.